my setup is in a 98 RS i now have the stock header to one stock cat a 2.25 inch piece of pipe instead of the second stock cat, then the stromung midpipe to a stromung dual tip muffler all 2.25
replace the stromung muffler with the 2.25 pipe and that was the straight system. It was what i thought was a noticable loss of power. It seemed to still have the low end but lost mid and top.
I dont know if that would provide enough backpressure for your car or not. I can just tell you the only thing it did for mine was make it loud as sin. But i drove it around like that for 3 days.
BTW i say it was loud as hell but trust me you cant even imagine
i head my friend take off from a friends shop over 3/4's mile away and i distinctly heard 1st 2nd and 3rd gear lol (was a low populated area so not too many large buildigns in the way)
Its now known as my "Fun pipe"
For those days that im more bored than others lol