A couple of weeks back and after 8 years I installed an MIVV pipe. It only comes in carbon fiber now.
I have a Beetle map installed for the stock pipe which was a huge improvement. That map works fine with the MIVV muffler which has a baffle installed. But to Pete’s point, if you do anything else, you should get the pipe first. It would be good if you could find someone close to you that knows the bike, to show you some things like others have done on this site. I was fortunate to get some assistance from someone on this site and we remapped and did the greasing and tuning etc.
Best of luck with the bike and you can find most answers by asking or going to the search tab.