FWIW, Herb Adams in his book Chassis Engineering gives some values with regard the impact of overall weight loss vs. rotating weight @ axle speed vs. rotating weight @ engine speed.

On a 3000# car with 428 hp, 15# of overall weight loss is equal to gaining 2.14hp = factor 1

15# of rotational weight @ axle speed is equal to 6.42hp = factor 3

15# of rotational weight @ engine speed is equal to 32.10hp = factor 15

Given that dropping flywheel weight on a street driven Evo is not such a great idea, that kind of leaves driveshaft and wheels as logical targets for improvement ...

 

Great book with cool info. Didn't think too many folks knew about that book.

 

The lighter wheels are covered,but the driveshaft? I think I've seen a 2 piece carbon driveshaft around. The 2piece would mean less of the need for solid motor mounts, with maybe a motor damper and slightly stiffer mounts needed?

 

AWD has 2 piece aluminum driveshafts which are more affordable.

 

AWD doesn't make them anymore.

 

I've got se37 rays Volks fitted 17x9.5 , can really tell the differance with the lighter wheels fitted just feels better all round

 

Wow, im deffinetly going to go with the stock bbs's or nto3's now thanks guys

 

i did a comparison many years ago a super lightweight 19" wheel w street tires, vs a 16" wheel with r compond tires.

on the 1/4 strip the lighter wheel/tire combo did 0.2 seconds and 1.5 mph faster.