The Dewbauchee Massacro from the High Life Update with ALL tuning parts included and fully usable, along with a moving steering wheel and HQ & LQ interior variants.
I've included the .max project file for anyone who wants to make their own fully tunable car.

REQUIRES v65.0 or newer of Zolika1351's Trainer/Mod Menu to work, otherwise the car is completely unusable. v65.5 recommended to avoid instability and to be able to purchase tuning parts in Pay 'n' Sprays (Vehicle Options - Pay 'n' Spray Mod Garages)
PUT MASSACRO.DAT INTO THE "carmods" FOLDER! (if it doesn't exist, create a folder called "carmods" in your game folder and put the .dat there)

Use https://gtaforums.com/topic/955449-iv-zolikapatch/ to make the steering wheel move

Vehicles.ide:
massacro, massacro, car, SUPERGT, SUPER, [email protected], NULL, 50, 5, 0.2747, 0.2747, 0, 5, 1.0 ,0, sports+wheelangle:-18.7
txdp
vehshareV, vehshare
massacro, vehshareV

Carcols.dat:
massacro, 0,0,50, 3,3,2, 7,7,5, 13,13,13, 34,34,30, 33,33,29, 0,0,96, 40,40,41, 57,57,55, 70,70,71, 72,72,73, 77,77,75, 88,88,50, 104,104,107, 121,121,123

Tuning part count: 28
Tuning part list:
Stock Hood
Carbon Hood
Race Vented Hood
Race Carbon Vented Hood
Low Level Spoiler
Carbon Low Level Spoiler
Race Wing
GT Wing
Stock Front Bumper
Carbon Splitter
Splitter
Carbon Race Splitter
Stock Rear Bumper
Rear Diffuser
Race Rear Diffuser
Stock Exhaust
Titanium Exhaust Tips
Stock Skirts
Side Skirt
Carbon Side Skirt
Race Side Skirt
Race Carbon Side Skirt
Roll Cage
Race Roll Cage
Stock Fenders
Race Wing Vents