Iv'e done 135mph in my old 86 325e with the same mods, except my exhaust was from Remus. You're not going to go any faster really. Of course turbo-ing it will help, but I honestly couldn't tell you of a kit just for the 2.7L but it'll probably be the same kit for the 2.5L You're probably better off going to a speed shop and have them custom build one for you. Keep in mind that it'll cost you more than your car is worth (no offence), and your engine will die sooner than later. How many miles on her?