When you say Muffler i assume you mean exhaust, i would not worry about that as quite a few GP's, mine included have needed new exhausts, due to hangers breaking. The scorched
JCW badge is also quite common again mine is scorched and illegible now after 27,000 miles. The tyre though is the one i would have a go at them for. Either it was low when you bought it a bit naughty or it has a tracking/suspension problem. Either way i would want a replacement ideally a pair as compensation. The scorched badge you might ask about but if its gone now it will do it again i should think!
How technical am i !!
Sorry you mentioned window, that is a bad one too. I would complain about that, nothing more annoying than a slow, squeeky window