I just did both my wife's 228 i and my 328 i wagon. A full paint correction was done on both then I used 2 coats of DPC Shield on them. I should have 18 - 24 months of protection.
After my first wash on the wagon I used a 600 CFM blower to blow the water off the car. EVERY drop rolled right off with no streaks. I didn't touch a towel to the car and it was perfect.
If you have the time and energy, the DPC Shield is $40 a bottle and you can probably get 6 applications out of the bottle. I've been polishing my cars with a DA for 10+ years, so it was no issue doing a paint correction then applying the ceramic coating afterwards.
