Got 3 questions about loosing some weight on the car:

Has anyone tried experimenting with a lighter radiator say, i.e. a Jeg's lightweight aluminum radiator?

Also has anyone tried aluminum pulleys on any inline 6s or V8s? would it make that much improvement? Maybe help revving quicker?

And third, anyone have any experience on aluminum driveshafts on mercedes? I've heard stories not to touch them as they are very well balanced but wouldn't a custom shaft be as good (if selected a good manufacture?)

The radiator is not he most weight, it is the glycol water solution. It weighs about 10lbs a gallon. My factory radiator is composite tanks with aluminum core is pretty light. A largr radiator might help with cooling though.

The pulleys might help get you about 2-5 peak horsepower on a 6 or 8 cylinder.

The drive shafts are pretty light already and I have yet to hear of one fail.

I Have The EVOSPORT power pullies on my W210 and They are good for a 8hp gain..I Did a Dyno Before and After They WORK!

How much horsepower and torque does your engine have before? If you look at it as a percent increased based on horsepower, if you assume a 305 hp engine, and added 8hp, that is about an 3% increase.

Yes, they work, but honestly, you can get +/-8 hp on dyno from a engine with 300 hp by changing fuel, using more viscus fluids in the engine and drivetrain, or at different ambient temperatures.

Power pulleys are a bigger numerical benefit on high HP engines or on high revving engines where the lighter weight is the benefit.

They are great if you need that extra edge in racing, but are really only cosmetic upgrades to a street car.

I pulled this out of my archive:

http://dinancars.com/html/danger_of_power_pulleys.htm