I need some help with two things

I currently have kooks 7/8 headers leading to 3.5 piping and an AeroTurbine exhaust followed by dual 2.5 tips. I want change it up by doing an 3 x pipe followed by two borla xr1s and 2- 4" dual exhaust tips. And maybe some cutouts later down the road. Would it be worth it performance wise or am I hurting myself? Mods are listed below

My second dilema is that I don't know whether to get my L92 heads p&p or add a stall. I can't choose because I just don't have the knowledge of which is better at the moment. If I get the p&p where should I look to go? If I get the stall is what are some of my options?

Any advice helps! Thanks!