I realise this is an old post but ill reply anyway as others could use some info...

I'm planning on swapping my stock cans for some custom fitted straight through (baffled) T4's.

but for now I did chop out a ring around the angled 1" end pipes to get some better sound. i then grounded the 1" pipe down flat. worked great! the actual hole didnt go right out to the side of the outer casing as theres about 10mm between a inner core and the outside casing.

hope i explained this ok. ill try posting some pics later....

this sounds so much better than standard!