You will defiantely lose power in the low rpm's. Back pressure is one of the things that helps make low end torque. i noticed quite a bit of loss in mine when i installed my O/R H pipe. What you will be doing is basically taking away all the backpressure and killing your low rpm power.

It will be loud though. People in the next county will hear ya coming. I personally dont like the straight pipe sound, to much drone, and it will pop bad when you let off the gas.

 

mine does too... relatively quiet and rumbly, until you get on it

 

O/r h pipe and loud mouth 1 catback.