The jag is way to heavy, even with 945hp. Plus it only has 5gears.
The Pennzoil Skyline doesn't turn very easily.
The R390 (road car I assume) turns horribly, and you cannot buy new suspension. All you can buy is turbos. The '97 R390 (the one you have to win in All Starts's race) is much faster and lighter. I've got that car running 15's in the 1000M w/no gameshark.
Out of your cars, I'd have to pick the M12. Lightweight, good powerband, and turns well.
Any car? I'd have to say get the Audi TT or RX-7 GT-C LM.