Hello -

I have a '97 D-90. Several years ago, I put larger pipes from the Catalytic converter back and a perfomance muffler on on the car. I am not sure if I got more horsepower. I think that exhaust sound increased a little. I was thinking about investing in an engine back system from NRP or BORLA. Has any one done this? Has it improved performance, MPG, anything else?

Please advise.

Thank you,

Syd