what turbo's are you GS's using?
 

Edit......

I'm running a PT67, .81 A/R. I can't remember what rpm it starts spooling/hits 18psi as I haven't driven the car in 3 weeks or so (broke my ankle and had to have surgery), but I can tell you it's one of, if not the most popular turbos for street cars (thought 63's are a popular choice but fall off on the top end). If I remember correctly the 67was rated the best street turbo across the board on Supraforums and I will say that on an Auto car it's definitely more fun to drive (responsive) on the street compared to my old 70mm.

If you want something super quick spooling look into something in the "GT" line(GT 35's are nice). whatever you do stay away from 60-1's and 62-1's, while they *were* a very popular turbo (back in the day) they will get outspooled and make less power than an equivalent GT series, you can actually go smaller on the GT turbo's for better spool and still make the topend of a "-1" turbo.

FWIW, if you were running a manual (though I doubt you are in this case) I would go larger, I was pretty pleased with my Pt 72 (GTQ/.81) on my old supra 6 speed, but again, that turbo would be a little much on an auto car without a high stall.

Edit......

You are probably going to lose some top end compared to the 67 with a 35r. It will spool considerable faster though, I want to say the Gt35r is maxed at about 550hp while the 67 should get you close to 650 at max. I don't think for everyday driving you would miss the top end of the 67 too much, though I definitely noticed my car did seem to lose a hair on the top though it generally dynoed within 10-15hp at peak of my 70mm. Around town it was much more responsive however and I only noticed the difference on highway pulls really.

I'm on a very basic fuel setup, I'm running a single Walbro with usdm TT injectors, custom resistor pack and the accompanying return fuel system to make it all work. Once I have some time to fiddle with the car I may go to a dual feed/dual pump setup but currently I'm within the safe area on fuel and in general am pulling fuel out under boost (AFC).

i thought the walbro is only good to 500? i'm guessing your pushing under 5 then....

I'm making just under 500 at the wheels, 467 to be exact.

I'm in the process of going turbo (piecing everything together) and I chose a GT3582R.

yea so you went with a gt35r...thats what i'm thinking of getting...but i'm worried because then i'll max out at about 525rwhp