The (original) defect had a hotdog under the passenger seat too - it was about 75Db inside
I drove it without the hotdog muffler once(straight through system) my ears ached for hours afterward
planning some kind of sound deadening with The Defect III as I like my hearing
The Iron Maiden (black car) has that hotdog now and is relatively quiet - but apart from no carpet it's has a full interior
as for doortrims - don't bother about removing them the weight loss is not worth it...