Ok i found out the remus cat-back's piping diameter...
it is 50.5mm
which is 1.9882inches!

2 inches? is this catback useless to me? i lovee the sound and the price and the quality, but, is 2 inches too small? i dont plan to turbo soon, but i would have liked piping that could have just barely tolerated it. isnt 2" stock?

 

That would be useless. 2" is probably stock diameter, if not less than stock diameter.