I cant't help with the pipes... I've done the bafflectomy already - but only the first one... that's loud enough for me.
However Brindle's questions...
With 2 baffles gone you probably would need a remap. Yes they fit. The MOT would depend on where you take it... My 03 has passed MOT's with one baffle removed, not even commented on....
Gina
03 America - Pretty stock - except the TBS wheel...

06 America - missing, presumed in bits. With it's TBS wheel...

09 America - It's very blue....