yes, right on the 3bar and the cam. Besides the oil squirters, sliders have a lot more drag. Putting a square tooth cam with a round tooth sprocket will screw up the cam timing too. Dont downgrade, stick to the roller. Forget the S60 too, it wears out WAY too quick. Either use the stocker (i am), or the 88 TBI seems to be a favorite. If you want a different grind, TAFT makes some. They make a S60 with less overlap and better wear (which reminds me, S60s suck for high(er) boost).

I would get a zener diode. Extra injectors or bigger ones. You shouldnt need an adjustable FPR if you go either of those routes. You could also just get a FPR and jack up the pressure a little. Save the ECU investment until you go all out (or buy my stuff). Its hard to tell when my T3/T4 spools, since i have an auto and the RPMs flare up way high instantly. Its really not too much more than stock (500 RPM?). Mine uses a .48 AR exhaust housing, CNCd to a S3 turbine. So spool is still pretty quick!

Gutting the cat, or putting on a good exhaust will give you huge gains. Then crank the boost to at least cutout.. stock fuel should cover that.