Are you wanting people to help you with a list of dfferent mods so you can create a catalog of mods for the forum or is this for your build thread? Just a little confused that's all
If it's for the forum I'll start
Engine:
Cold air induction kits
Panel air filters
Engine mounts
Turbo K03/K04/Hybrid/etc etc
High pressure fuel pump
Low pressure fuel pump
Strut brace - not sure if you class that as handling or engine mods
Radiator S3/Forge etc etc
Remap
Diverter valve
Cam follower
PCV / blanking plate
Spark plugs
R8 coilpacks
Batteries
Silicone hoses along with any necessary clamps?
Engine oils if that's a mod?
Also in the brakes don't forget braided hoses, brake fluids, types of discs (grooved/dimpled/drilled/j-hooked) (vented)?
Dash/Interior:
Radio: RNS/RCD310/510/DAB
Canbus Gateway swap
Bluetooth module
Cherry red hazard switch
MK6 chrome tipped switches
Armrest
LED lights
MDI dock
MK6 MFSW
Highline clocks
Cruise control stalk
Door warning lights
Seat inlays
Seat change: I.e R32 bucket seats
Heated seat install
MK6 climate control panel
Hope I got the right idea from reading your thread
Will leave the rest for other people to have some input