I use all my friends tunes or ask never had experience in tuning cars
This car is a special case, because no matter what tune you put on it, you will need to drive a little differently.
Tuning isn't an 'off' or 'on' thing. It doesn't just make a car 'good' or 'bad', and you don't even need a tune to drift. In fact, I would guess that
about 75% of all tunes are actually worse than stock or the default settings for drifting. They might be 'easier', but the result when you drive well is actually worse.
Tuning is a continuum. The cars can always drift, you just decide
how they drift by giving it a tune. They never become 'bad' or 'good', they just get 'better' or 'worse' in certain situations. See what I mean?
So if you just want to drift the car, there's no point in putting a tune on it. Just learn to drive better. But if you want to drift
well, you can put a tune on it, but for cars like the S2000 GT1 Turbo that require you to change your driving, you won't be able to drift it properly (maybe you can drift, but not well) until you can both adjust your driving and tuning at the same time.
In other words, If you don't know how to drive the car well, using other people's tunes might make you worse. If you don't know how to tune well, driving an unusual car (aka S2000 GT1 Turbo) will make you worse. If you can drive well, you can make the most out of a single tune. If you can tune well, you can make any car decent, but not get the best out of it.
The best, of course, is to drive well and tune well. Then you can make the most of any car.