Yeah Matt head unit is easy and the same as the is300 so a direct switch yours for theirs would be very straight forward to change not seen many cut jobs as you still need to bypass the amp and the leads are very easy to pic up on ebay. If you buy the 300 giz a message and I will be happy to give you some advice on removal. Don't forget only bad point i see of having a 300 is parts engine only as everything else is pretty much the same but I guess engine parts can be very rare is200 parts are so easy to get.
As for this keep moving back to 300 better then 200 I think both cars have their charm and I love them both I mean come on its only really the engine and auto bar that they are like twins well a bit like the movie twins ones way more powerful and the little fella is fun and not on steroids.
I found the 300 very fun to drive and do envy the power but I guess that's what superchargers are for.
Cheers Dave