I talked to Alan at Modbargains a bit ago about making a rotary forged ZHP replica in 18", similar to the Sportline CS 16 CSL replicas in 18". Their construction would be similar to that of the Apex ARC-8 18", which should make them around as strong as our stock wheels- which are actually quite strong.

The 18x8.5" CSL rep weighs 19.8lbs, the 18x9.5" version weighs 19.6lbs. I think the zhp replicas would be similar in weight- maybe a bit heavier. We'd need 20-30 orders, which is steep, but this seems like it could be a great opportunity. Any interest? Keep the stock look and drop 7-8lbs per wheel!

Here are the Modbargains CSL Replicas just as an example:

http://www.modbargains.com/Sportline...Wheels-BMW.htm

Lower weight will give you:
- Much better throttle response
- Better gas mileage
- More responsive handling, quicker braking
- A smoother ride
- Crisper turn in
- The feel of more horsepower

A quote from the Pelican Parts Forum:

Track results tend to look better than paper calculations, but something like .5 hp per lb doesn't seem too far off for a 3000 lb 300 hp car. Here is a link to the thread, and the body of the main post.

http://www.rx8club.com/archive/index.php/t-3681.html

Quick summary. Some 6 owners have done back to back comparisons on the track comparing 18x8 rx8 rims (with stock tires), vs 16x8 rx7 rims (14 lbs less a corner) with similar diameter tires...and have dropped as much as 0.5 off their 1/4 time. In almost all the situations, the rx7 wheels were usually in a condition which wasn't favorable for good results, but regardless, a significantly acceleration difference was noted.

The performance benefits from reducing unsprung weight and rotational inertia are far greater then they seem on paper. This is of course completely ignoring the additional benefits to braking and handling which results from dropping unsprung weight.
Here is some info on the benefits of reducing unsprung weight:

http://www.tirerack.com/wheels/tech/....jsp?techid=98

http://www.caranddriver.com/features...d-tires-tested

The amount wheel weight affects straight line performance is the most debatable of the benefits, however there are certainly no downsides!