Hi Laurens
Tools for the job:
Cordless drill.
45cm long 3/8" drive extension bar.
Chuck adaptor to drive the extension.
38mm hole cutter, you will probably need 3 of these.
Socket to drive the hole cutter.
Hammer.
Method:
1. Remove exhaust pipe and secure in a vice being careful not to crush the pipe.
2. Attach hole cutter to extension bar and hold in place with some insulating tape. The tape is just to stop it falling out of the socket.
3. Slide the hole cutter down the exhaust pipe from the front until it touches the first baffle.
4. Give the extension a sharp tap with the hammer, this will centre punch the baffle with the pilot drill so it will not wander when drilling.
5. Attach hole cutter and extension to drill and off you go, nice and steady remember it is stainless steel and very hard. Use cutting oil or tapping grease to lubricate.
There are 3 baffles in each exhaust, 1 in front of the silencer and 2 behind.
It took me about 20 minutes per baffle to drill out and I blunted 3 hole cutters, don't buy cheap ones, as if you would.