Re: How about the Corvette Magnesium wheels?
I thought they were really cool looking and did some digging a year or so ago.
Here's what I found:
1.) They're really expensive. They were a $3k option on vettes, so there weren't that many sets produced, and the vette guys know it. And breakage has taken its toll, too.
2.) They don't hold their finish well. The clearcoat flakes off, because its difficult to get it to stick to magnesium properly. And be careful buying refinished wheels, because magnesium turns black when exposed to air (so if you've got a clearcoat that isn't air-tight, they'll turn black under the clear).
3.) They're not all that much lighter. They're about 1.5 to 2 lbs lighter than the same size GM alum wheels (like the Y2K vette wheel). They're about 3 to 4 lbs lighter than the '97 to '99 Wagon Wheels. The Z06 wheels for the C5 are about the same weight at the Y2k wheel and are an inch wider (but only the factory wheels which were either spuncast or forged, the reproductions are like 8 lbs heavier than stock). If you want really light wheels, look for aftermarket lightweight ones.
4.) As mentioned above, the vette sizes are 17" x 8.5" fronts and 18" x 9.5" rears, Z06's are 1" wider (front and rear). Which means you've got to mix and match tire sizes accordingly. And getting a full set of 17's or 18's is a bit more difficult.
5.) Aluminum and Magnesium are fairly comparable strength-wise as a generalization. Certain magnesium alloys may be stronger than some alum alloys, but by and large, its a wash. There are alum alloys (like 2024 or better yet 7075) that would be significantly stronger than any magnesium available, but they're not likely to be available as anything but billet or forged alum wheels (and still unlikely). Magnesium is about 2/3rds the weight of aluminum. Last note, magnesiums compressive strength is markedly lower than its tensile strength (in almost any wrought alloy) which means high strength magnesium forgings don't get you nearly as far as alum or steel forgings (where compressive and tensile strengths are nearly equal for a given alloy).
Basically, they look nice, but in my opinion they're not really worth the money folks want for them. They're tough to keep good looking (because the clearcoat pops off) and they're not that much lighter than stock wheels. If you want lightweight, look for lightweight aftermarket wheels (like BBS's and such) and expect to pay for that lightness. If you're just looking for a look, they're more trouble than the cost is worth.
'JustDreamin'