I've had a lot of success with Rennwerks...they specialize in BMW's and Porsche's and have a racing team with both manufacturers...many people use these guys and they are stand up...really know what they are doing...if i had the money i would have them install my suspension but i'd rather DIY...
You dont really need to pay hella money for good install. Go check out AutoInnovations in Milpitas. If you want springs/shocks installed, they'll charge you 320-350 with alignment.
If you do go there, ask for orlando, tell him patrick sent ya.
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