No thats just the powerband of the motor man. A set of cams would help the topend and I think JWT is the only one with a ga16 cam out. The GA again is very tough to make even try to keep up with a stock SR20. I played with the ga16 a long long time ago and it was just not worth the money put into it for so little performance. Back in 98 i used to have an auto nx1600 and even fully bolted on it ran 18.2@76mph, granted if it was manual it would have probably went a 17.2 or so but it was slow as balls and I hated it so I sold it and got an SE-R which I had wanted for a long long time and even with rod knock and running on 3 cylinders when I first got it I took it to the track and ran 16.3@87mph just as it was, then put a jdm motor in it and finished up the bolt ons on it and was in the 14.7 @94mph, then did cams and was 14.3@97mph. Just simple bolt ons. Even turboing yours probably wouldnt keep up with a fully bolted on DE.
I know you want to keep the ga and all but I would highly recommend ditching it if you want to go faster and want more power. Save that 120.00 that you would have spent on a window switch and whatever you wanted to spend on the turbo kit and get yourself an SR setup. The swap is simple and easy, pretty straight forward.