At the moment I run either 15x7 ET0 with a 25mm spacers, or a 15x8 ET-8 no spacer, superlight/watanabe copies, from Palmside.
Weighing them without tyres, the 15x7 is 7.9kg and the 15x8 is 8.3kg. The 15x8 ends up being the lighter option as the wheel spacer needed with the 15x7 is 1.2kg.
Being NA, my setup is all about response. Toda fly wheel, ITB's, I've binned the PS as well.
Looking at TE37v's in 15x8.5 -5; these weigh only 5.3kg. That's at least 3kg less of unsprung weight per corner. 6kg less that the motor has to spin up.
How greater affect will this have? Difficult to measure. Obviously it will have some, but will it be significant?
I quite like drifting on my current wheels, they look good for copies, they're less than $200 each, which means I don't really care about them. They're tough as shit as well.
The volks would be closer to $1k per wheel, and I'd need 10 minimum. And the thought of drifting on Volks is

That said, getting more power out of the beams will cost a shit load, and I'm not all that keen as I love ringing it without mercy.
Any experience on dropping so much wheel weight??