Kev - Thanks. Like you, I really wanted to do the Euro seat bottoms but with an individual interior, I don't think I'll be able to get the covers. The US bottoms are a huge pet peeve. You did a nice job on that.
Ersin - I hear you. I'm not sure about the exhaust. I really like the OEM sound and don't want to mess with it. That's why I was thinking about the Turner test pipes which delete the primary cats and leave the rest. Yeah, the detector is a must. I won't do it unless I can do it right and $2500 is pricey. I'll just end up swallowing it I guess.
I think If I add the Alcantara headliner and Zwick dash to the individual interior the interior will be comparable to an M5 / M6 interior, albeit for a bump price. Zwick made that really nice but slightly over-leathered interior on their M3. There was some nice elements there. I haven't called them yet, but I'm sure it's like anything else - for a price they'll make it.