None of that will do much.
Being a maf based system leaves you with some delay.
Engine doesnt make much power so after 60/70% tps, it will all feel the same.
Only thing you can do without sacrificing low end would be opening up your lim.
As far as handling, youd want sway bars in there too, lowering isnt good for handling. Throws the suspension geometry off.
Higher the spring rate, the less body roll you'll encounter.
But the ride will get worse as you go, even with quality struts.
Any higher than the spring rates you find with lowering springs and youd probably end up floating over irregularities in the road. Not good lol.
Stb's arent worth it to me, the chassis is still too loose even after both stb's have been installed.
For sway bars you might want to consider the gmpp kit as its the least expensive. After that you have the dorman front bar with an addco rear. They're both solid, larger than stock yet smaller and cheaper than slp bars from 3800 performance.
I have vogtland springs with bilstein hd struts. Great feedback from the road yet its not overbearing or unpleasant. Alao note that combo results in stock ride height.
Catback is 110% waste of time.
Wont sound pleasing nor will you net any power from it.
