I don't know if a slower car would help. If you cronically speed you're probably going to do it in whatever car you're in. I know it's lame, but learn to watch your speed, be mature about it and slow down. Don't feel like you have to go faster than everyone else. It doesn't really impress people if you speed. It may be fun for you, but it usually scares the heck out of people, or if they aren't scared they just think you are stupid. You can actually clip along at a good pace if you go faster than about 80-90 percent of traffic, but keep it slower than the other 10-20 percent. Let the other 10-20 grab the cops' attention.
If you persist on speeding learn to scan. You cannot be distracted while going fast. All of your attention must be kept on traffic patterns and awareness of cops. Don't blow through underpasses, cops like to hide on the other side. Watch on ramps, cops love to get on and just nab somebody. Clumps of traffic are huge speed traps. Cops will sit in those surrounded by cars or behind a big truck, and then jump on your tail as you tear by. Finally, don't weave traffic, this just screams, "pull me over please". I have seen many people get nailed for speeding because they were weaving traffic. Don't do it.
With all that said, I hope things work out for you. Good luck bro.