Most good Indys have diag setups
Most good Indys have diag setups
And although there is a lot electronic modules in these cars they are still
internal combustion engines. Plus there is a law that says repair knowledge must
be made public and a good Indy will be connected to the TSB technical service bulletin
database.
There are a group of websites that cater to people that can even reprogram some of the
functions of the car and do aftermarket software changes to hot rod it.
If you are interested enough you can get a coding setup that will allow you to do diags
and recode the car for less than 100 bucks.
see
bmwcoders.com
http://www.e90post.com/forums/forumdisplay.php?f=368
http://www.e90post.com/forums/forumdisplay.php?f=16
The independents will have less experience on the new models but a good Indy can be much
better than a bad dealer. And there is quite a bit of difference between dealers.
Its a good idea to search these sites and find out what the common problems and solutions
for your particular model .
On the 335 you probably should have an Intake cleaning every 60 to 70k due to carbon build up.
The problem area's on 335 are the turbo hardware and injectors.
expect a water pump change at some point for any model probably around 100k miles
Also change out the lifetime fluids if you want the car to last.
Google Mike Miller BMW for the old school maintenance schedule for guidelines.