I have a 1999 Grand Prix GT, everything is stock on it.

I'm not too knowledgeable about exhaust systems and was wondering if I could get some help..

I'm looking to replace the stock muffler and exhaust tips with aftermarket..but honestly can't do it myself without a little advice/help...

-Flowmaster 40 exhaust/dual tips??
OR
-Cut off exhaust and straight pipe with stock exhaust tips.

Which one is cheaper? Will sound better? And which one is easier to do myself?

Thanks,
Ryan