I've Just drilled my 96 TBird pipes. Dead easy and it sounds great. I used a 25mm core drill in a Mandrill from B&Q cost about £6.00. Used araldite to fix the mandrill into a 9mm socket - fixed the socket onto a 12 " extension piece from B&Q - about £10.00 left it overnight to set. Took the pipes off the bike leaving the mounting bracket on the pipes. Removed the brackets and bolts from the pipe. Found 2 bolts of the same thread and length - screwed them into the holes in the pipe and used these to hold the pipe horizontal in a vice. Then driling from the manifold end of the pipe at about 8" in sits the baffle plate - drill out the baffle plate - 10 seconds - job done - Dead easy. Previously though I went to a local engineering company and they wanted £80.00 to do the job and then asked me how they should do it - yeh!! :-D
No Problem just be sure you blow the silencer clean afterwards. I just welled a 12mm dril at the end of a 30 cm long steel rod and drilled 3 holes in each silencer... now it sounds and rides great
None, it just sounds good! It's not a lot louder than stock, especially at low revs and it does pop on over-run, which I love but others dislike. Best of all it's easy and doesn't cost much!