Those problems sounds normal to me although I don't own a 335. If everything checks out fine and you're a DIY guy then why not right? I don't know why people are so afraid of a high mileage BMW or any luxury cars. Reliability has improved on cars in general over the last decade. My car has 155K+ miles and has been great, but then again N52's are good cars. Just my 2 cents.
Mod clean my friends.