There was an article a done by Car Craft (I think) a while back with the same test, how much a difference light-weight wheels really make, and when compared to heavy steel wheels it was hardly worth any E.T. or MPH at the track. The rims on my car now are steel and I only felt okay about buying them after reading that article. Besides, the stock rims are heavy too, so it's not like your car would be any slower if you switched to different steel rims.
Managed to find that article, here's the results they had during their test...
Total weight reduction = 82.08 lbs.
Total performance gain = -0.111 sec, +1.12 mph
Light Wheels Vs Heavy Wheels - Wheel Tech - Comparison - Car Craft
Not worth it in my opinion. If you like a certain set of steel wheels, get them!
This is a good example of how hype can spread through a car community. Get a handful of people preaching about how aluminum wheels and less unsprung weight will shave seconds off of your track time, and suddenly everyone hates steel wheels. Thankfully there are publications like Car Craft to actually test these theories and get true results.
If your car spends most of its life at the track and 1mph or one tenth of a second means the world to you, then maybe the extra expense of lighter wheels is worth it to you. Other than that...
