Re: my journey begins
For the stripped screw head, you can most likely coax it out if you have an impact driver. You can get one with a bit set from most auto parts stores for fairly cheap, just make sure it's set in reverse before striking it with the hammer. This tool is a very good investment for anyone working on these or on motorcycles... or basically anything that's aluminum or die cast metal that has standard or phillips screws holding it together...
As for the pipe, that bike I built for a customer, I just used the stock pipe but drilled 5 5/16" holes thru the end cap and didn't even mess with the inner baffles. The engine was still nice and quiet after the holes were drilled but the torque was amazing combined with the mild port job I did, that engine was basically ports widened 1mm on each side of the intake and exhaust ports, head shaved down 1mm, casting ridge removed from transfer roofs, and I ramped the piston at the transfer openings only and cut 5mm off thte skirt on the intake side... took me all of about 30 minutes to do the port work, I didn't want it to be a screamer but since this customer was on the heavy side I did want better torque, but didn't expect it to make the crazy amount of torque it did, I was expecting it to be a little stronger but it turned out a LOT stronger and was still able to get above 30mph on top.
Yours should have similar or better torque with that really wide exhaust port if you can also get similar compression