The S-trim implements straight cut gears which makes it REALLY loud. The SQ stands for "super quiet", so you do the math.
The SQ's use 3.61 gears which allows it to spool quicker than the 3.45 geared S-trim.
So, there's pro's and cons for both.....SQ spools quicker but is quiet. The S doesn't spool as quickly but is LOUD
As for boost on a stock motor, I wouldn't worry about the amount of boost as much as I would worry about the amount of power being made. The stock motor can only handle around 400rwhp safely. I wouldn't go more than 8psi.
Ok guys well i'm going to go with either one of these not sure which one yet. But probably the s-trim and go btw with it and if it blows the motor i'll just get it built.