Those cars look great. I have a jet black car and it's a pain!
I use Optimum products and they're great. I've only tried the OP and Optimum Poli-seal so far though. I'm debating if I should get the OC or OHC and get out heavy scratches myself or if I should have it done....
The light swirls I got out easily but there are what looks like heavy brush marks(motorhome brush) from the dealers wash that I couldn't get out with the OP.
p.s. my last car was a 350Z, fun car but the 3 series is a much nicer car to drive and still lots of fun.