just a note, and i am sure this goes for the platinum achievement as well that using a B class car (in my case the Enzo, opposed to the F50 GT) is much easier during street races, also using a lower class car during breakthrough, hot lap and timed runs gives you more time which can really help. All times are listed in this walk though found on GameFAQs posted by TwistidSoul
http://www.gamefaqs.com/xbox360/927245-project-gotham-racing...