RemainVayne

Right - that's so your check engine light doesn't come on.

Cruehead

I love it loud...but the o/r pipe was way too loud for me...so I took it off and put the stock mid pipe back on. I will be trying the o/r pipe with the stock cans when I get the time.

desslok40

I had the same issue after install of SLP LT headers and X-pipe with Cats, check engine light came on today, log shows some O2 Sensor issue, Brent is sending me new tune to correct issue, damn computers !!!!

talios

SLPs alone give a much nicer tone and a tad more rumble than stock imo.
O/R pipe with stock cans gives about the stock tone just a little bit louder, not as loud or nice as the SLPs alone.
O/R pipe and SLPs at the sametime rumbles, roars, screams, etc no matter how you baby it...sounds nice and all, and if I thought I wouldn't get pulled over I'd have left mine on. Although if you shift under 2k and baby it it's pretty quiet tho, haha! In the two days I had them both in I had multiple people pull up next to me and ask what kind of motor I had put in the car. [sm=grin.gif] So ya, if you don't mind a ticket have fun with it...