2.5 Exhaust back pressure/ exhaust piping kits for Xj

So I’m gonna pull the trigger redo my entire exhaust system that is badly needed for my stock 2001 XJ.

I’m going to run everything 2.5” stainless steel piping.

A few questions.

1) Back pressure?
I’m hoping to increase front end HP and not get any back pressure with the 2.5” piping by compensating with a 62mm TB + CIA+ map adj. sensor +12 hole injectors (I watched a video that dyno’d 12 injectors and it Increase back end torque.). You think this combo would eliminate back pressure?

2) I’ve decided to buy Flow master 40.
*I was wondering if there are any piping kits out there that would direct fit “plug and play” piping without having to modify or add any additional piping? I’d rather do it myself but don’t have tools to cut and weld.

Thanks fellas!

Dsf


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