Honestly I wouldn't recommend getting a 335i without CPO because repairs can be extremely expensive but it's perfectly fine if you have money aside for repairs. Things you should look for, 07' you should get one with sports package as it will come with the oil cooler (oil cooler is located in the front wheel well), try to see if there are signs that show the car has been modded. Also look for a car with good documentation of service records so you know if the car had past issues and the last one would be to get a PPI done at either an indy shop or a BMW dealer. That's all I can come up with now, hopefully someone else can add on with more information.
10' Space Grey e92 335i