Hi paddockman, welcome to the forum!
When I created the specification for my Plus 4 ( 2018 model), I also dealt with the subject of exhaust for a long time (one wants to have a nice sound). I then decided on the original exhaust (you can change an exhaust later if necessary) and am very happy about it. The sound is very good and not too loud. The sound has changed during the first few hundred kilometres and is now really fine. Performance improvement was not an issue for me.
