tight fit for sure..
i agree with you i just got mine & love items cousin has one on his M3 and i loved the note it produced not to mention the craftsmanship is so perfect cant wait to do headers & h pipe without cats so dam mean sounding pure power sound no raspy rice burner sound esp that i have the 4.2 liter motor
Wow sounds great just how I like it deep throaty rumble it reminds me of mine I went with Billy Boat Performance Sport model It screams in & out of the car & the price is right the craftsmanship is excellent as well it is easy to install as well I love the Armytrix is great with all the features but the price is crazygracing, Very few on here will be aware of the PES exhaust. They've only just entered this market. The S5 exhaust is as far as I'm aware about to launch and will be competively priced. Their exhaust systems are made by a very well known exhaust manufacture in the UK that specialises in Ferrari's and other such exotics so if that's the sort of sound you're after you probably couldn't go wrong! Here's a teaser of their new R8 exhaust (think you'll agree it sounds awsome)....
As for a tune (chip), it's horses for courses on the V8, they all do approx the same. That being the most you'll notice is increase throttle response as the gains are no more than 20hp/25tq by any supplier, there just isn't much left to ring out of this engine without heavily modding it.