Tunable cars

Hello everyone, I've seen some comments on my cars from people that want tunable cars, just like in GTA V, but, per example, the 9F isn't tunable, and, why? The Cheetah is tunable, right?
Yes it is, but, there are some details I'm going to explain here.

Cheetah's tuning is on Transfender, just like other cars, like the Blista Compact, Nebula, Clover, etc, but there is a slight problem on cars that are tuned on Transfenders.

Transfender uses a group of generic parts, and by generic parts I mean, the spoiler you tuned on the Cheetah is the same as the one you will tune on a Blista, same goes to exhausts, vents, side skirts, etc.
So, with all that being said, if I wanted to make the 9F tunable, it would have the old ugly GTA SA tuning parts, and they would not match the car.

"Well, but you could just change the parts, right?" Yes, I could, but then a blista would have a 9F spoiler, a 9F exhaust, and some of you might think that that is nice, but, imagine I would release another car for, per example, the Nebula, I would change the parts, and then the 9F would have the Nebula's parts, and vice-versa.

"Alright, alright, so, let's take the Transfender away, and bring the Wheel Arch Angels, what's your excuse now?" GTA SA Wheel Arch Angels cars consist on the following tuning scheme - 2 exhausts, 2 front bumpers, 2 rear bumpers, 2 side skirts, 2 roof scoops, 2 spoilers and 3 paintjobs, but, as we all know, GTA V cars aren't like that, some even have parts like bonnets, and wings, etc, and the problem here is, per example, a tunable bonnet.

The way GTA SA tuning is set, I can't make a tunable bonnet with the same reliability as a front bumper in terms of bugs, and then, making the bonnet damageable would be another impossible thing.

And then, we have other problems, since GTA SA tuning is limited to 2 parts on each zone, I can't put the 3 spoilers that the car on GTA V has available.

So, that means the Zentorno will have no tuning, and it will replace the Infernus, even though it can be tuned on Transfender, it has no parts, but, I think I can get something around that problem...