I have some advice that is a little different than what others are saying. Everything they are saying, espcially with regards to slowing down and focusing on ONLY driving is spot on.

That said, I highly recommend taking a high performance driving course, the kind that teaches you threshold breaking, puts you on a skid pad, and maybe even puts you on a race course. I've done this a few times (lucky enough to have a family mamber who races Porches, so cost was somewhat managable) and it has made me a much better driver for a number of reasons:

1) You will learn what the car feels like at its limits, in a safe environment. This helps you never go near the limits on the street.

2) You will learn how to recover if you exceed the car's limits. Hopefully you will never need to do this on the street, but it's good to know how.

3) You will get the need for speed out of your system. Driving close to the limits can be fun. Do it in a controlled environment, and it can be relatively safe. DON"T DO IT ON THE STREET!!!

After every track day I have driven, I find myself driving much slower and more carefully on the street, and I think the experience has made me a much better driver.

You seem like a reasonable and careful kind of guy, which is why I am suggesting this. If you are the type who will take this kind of class and think it makes him a better street racer, well then ignore everything I have said, as it may only get you killed.