exhuast, upper contorl arms and cool air intake questions

1.I have a 1990 jeep cherokee with a pacesetter header and a super 44 flowmaster on it. I was curious to here if anyone has tried or done a dual exhuast set up on a cherokee and how they did it?

2.My xj also has rancho lower control arms, coil springs and shocks on it. I want to replace my upper control arms but don't want to go stock, I want to go with something stronger any ideas?

3.Final question. I want to get a cool intake but seems to be none for the renix 4.0, so would a kn cool air intake for a 91 xj work on the 90? could i mod it, i did think about trying to make my own.

thanks

3.) If you do a search on the intake systems, you may find the survey thread that was done. Many good examples. I liked the ones hooking into the cowl plenum.
1.) Dual exhaust is a waste on an inline six (you don't say what you have). The easiest way to do it would be to use a single inlet, dual outlet muffler.

Rusty's air tube for the Renix:

http://rustysoffroad.com/mm5/mercha...Product_Code=RP-AT11-XJ&Category_Code=PER_AIR