
High Speed 5"
Here you'll find links to the best performing products for 5" freestyle drones based on my testing over on AOS Labs and my own experience and research. Some of these links are affiliate links (affiliate policy).
Motors

EMAX Pro 2808 1900KV
This Emax Pro motor is a lower cost option for high speed 5" flying. I used this motor for some of my test flights and can confirm it will hit 200mph on 6S. On 8S it will certainly go even faster. Not recommended for multiple consecutive high speed runs as its multicore windings get hotter than the single core windings found on more premium motors.

T-Motor VELOX V2808 1950KV
A 2808 size motor at 1950KV is ideal for 200mph+ flights on a 6S 1800mAh and even higher speeds on an 8S 1300mAh. The diameter of the motor also perfectly matches the arm shrouds on the HS5 for the lowest drag.

XNOVA 2808 1900KV
XNOVA make premium motors with excellent performance. This 2808 1900KV motor is perfect for high speed flying on 6-8S. The thick single core windings will help the motor stay cool at high power outputs and the motor diameter is matched to the fairings on the HS5.
Electronics Stack

DYS F7 Stack - F722 FC + 65A 2-8S AM_32 4-in-1 ESC - ICM42688P - 30x30
This is a great value stack from DYS that runs AM32 and supports up to 8S battery voltage. A 12V/3A BEC can be used to power VTXs that don't support 8S. This is a really impressive stack for the price.

T-Motor F55A PRO III 55A 3-8S BLHeli_32 4-in-1 ESC - 30x30
Funny story, T-Motor released this as a 6S ESC. Turns out it was so overengineered it supports 8S no problem! Now, T-Motor are marketing it as an 8S ESC. This a great option for up to 8" drones on 8S. Requires a flight controller that can handle 8S input voltage.

T-Motor F7 PRO Flight Controller w/ WiFi + Bluetooth
A solid 8S capable flight controller that can direcly plug into the Cine55A 8in1 ESC for an X8 solution. Supports Wifi and Bluetooth connection to Speedybee app for firmware flashing, configuration, and blackbox analysis. Very useful for tuning large drones in the field where the USB port is not easily accessible. 10V/2A BEC to provide power for a VTX that's not 8S compatible.

T-Motor Velox F7 SE 50A Stack
An F7 flight controller with Bluetooth connectivity, plugs for everything as well as pads for direct soldering and 8 motor outputs. The ESC is rated for 50A and runs BLHeli_32. And it's made by T-motor so the quality should be good. Great value at $90 USD.

SpeedyBee F405 V4 Stack - F4 V4 FC + 55A BLHeli_S ESC - 30x30
A great budget stack for a larger 6-7" quad. For 5" I have moved to 20x20 M3 stacks as they have plenty of capability in a smaller and lighter form factor. Don't get upsold to an F7 or BLHeli_32 ESC I have yet to find anyone who can tell the difference even when tuned to the limit.

SkyStars Fly Stack - F722 HD Pro 4 FC + AM60 60A AM_32 ESC - 30x30
The big brother of the Skystars F722 Mini. This is overkill for a 5" quad but perfect for a larger 6 - 8" build. The 60A AM_32 ESC will put anything else to shame. I've torture tested it's little brother the KM55A and found it incredibly durable. For a high power 6 - 8" build this is what I would buy today.

Skystars Fly Stack - H743 Dual Gyro HD FC + KM60 60A BLHeli_32 4-in-1 ESC - 30x30
An H7 processor is total overkill for flight controllers today. It has far more performance than Betaflight needs even running everything at an 8K loop rate. That said some pilots have their heart set on H7 and this offering from Skystars is a good value option with an ESC suitable for 7" drones.

T-Motor F7 Stack - F7 FC, F55A PRO II 3-6S 4-in-1 ESC Combo
T-motor have the best reputation for quality and durability in FPV. This is a fully featured F7 stack with a bulletproof 55A ESC. Overkill for 5" quads but 6-7" builds will benefit from the higher current rating.
VTX

Walksnail Moonlight Kit 4K Avatar VTX Kit
The top of the line Walksnail Avatar VTX. Onboard 4k60 recording and 1080p60 or 720p100 video in the goggles. The image quality is not as good as DJI O3 but the price is much more reasonable and this camera does better in low light.

DJI O3
The DJI O3 system pushes digital FPV in a new direction. Here the focus is onboard recording and image quality at the expense of latency. It is a great looking system, some pilots are reporting issues with vibration sensitivity of the IMU used for electronic image stabilisation, hopefully this will be resolved in a future firmware update.
Receiver

ES900 DUAL RX ELRS Diversity Receiver
If you're flying Long Range alone or with only a couple of others 900MHz ELRS provides the ultimate in range and penetration. This true diversity (not just antenna diversity) receiver from Happymodel gives you two antennas and two opportunities to receive each packet sent from the radio. Two opportunities means half the chance the quad falls out of the sky!

RadioMaster RP4TD ELRS 2.4G True Diversity Receiver
Radiomaster is a reliable manufacturer of ELRS equipment and this true diversity 2.4GHz receiver (not just 2 antennas but two full receivers working together) is a great choice when you're looking for a very strong and reliable link over medium to long range.

MATEKSYS ExpressLRS 2.4GHz Receiver - ELRS R24 TD
I've made my mind up. I'm only recommending ELRS moving forward. At this point it does everything better than any other radio link. LoRa for range and penetration, yes. 1000Hz update rate for crazy low latency, yes. Loads of manufacturers are making receivers for ELRS and I think this diversity offering from Matek (antenna diversity only) is certainly among the best performing and most reliable.

Happymodel ExpressLRS Nano 2.4GHz EP1 RX
Happymodel were the first to bring out ELRS hardware and their EP1 and EP2 receivers closely follow the developers reference design and are incredibly tiny. I lean towards the EP1 as the UFL antenna is much higher performing than the ceramic antenna on the EP2.
Props

APC 5.25x8E and 5.25x8EP
Tested to well over 200mph by Luke Bell on Peregreen. Make sure to buy both the "E" (CW) and "EP" (CCW) versions.

HQ 5.3x8 Props
Tested to over 200mph on 6S and capable of even higher speeds on 8S this is my recommended prop for the AOS HS5. Be sure to buy both CW and CCW versions.
Batteries

DOGCOM 1300mAh 150C 8S LiPo
DOGCOM are consistently among the highest performing batteries in each size class. This 1300mAh 150C 8S pack fits neatly into the HS5 battery bay and deliver blisteringly fast top speeds with similar endurance (Wh) to a 6S setup

TATTU R-Line V4.0 1300mAh 130C 8S LiPo
The Tattu R-Line V4.0 batteries are high quality packs with excellent power delivery under high load. This 1300mAh 8S will fit perfectly in the HS5 and give you significantly higher top speeds than a 6S 1800mAH setup.

GNB 1300mAh 120C 8S LiHv
GNB make batteries with good energy density and price/performance ratio. This 8S LiHV 1300mAh may give a little more top speed when fully charged but voltage sag towards the end of the pack tends to be slightly more than a traditional top quality LiPo. It's also a little lighter weight.

GNB 1850mAh 120C 6S LiHv
GNB make batteries with good energy density and price/performance ratio. This LiHV 1850mAh may give a little more top speed when fully charged but voltage sag towards the end of the pack tends to be slightly more than a traditional top quality LiPo.

DOGCOM 6S 1850mAh 150C LiPo
DOGCOM are consistently among the highest performing batteries in each size class. This 1850mAh 150C pack has got the juice for multiple high speed runs and fits neatly into the HS5 battery bay.

TATTU R-Line V5.0 1800mAh 150C 6S LiPo
The Tattu R-Line V5.0 batteries are exceptionally high performing packs. The 1800mAh will fit perfectly in the HS5 and give you great flight time as well as plenty of power for multiple high speed runs in a single pack.