[quote]Really, what it comes down to this question for me: has the JHM crank pulley been proven to minimize the vibration that Audi thought was problematic enough to use a more expensive damper? The manual talks about stress reduction on the crankshaft, and I’m not in the position to disagree, so for me personally it’s not worth it. I’ve done this dance in the Porsche world with mixed results, so I’m less enthusiastic now.
[/quote]
Well honestly, we’re not talking about a serpentine belt; there’s only one accessory that’s driven by belt… The LW Pulley from JHM is also counterbalanced at (I’m assuming), the correct point to offset the harmonics from the main counterbalance. I’ve done full LW pulleys on various cars for years and while the comment is correct that it adds zero to a dyno sheet, the effects on throttle response can sometimes be pretty dramatic. IMO, if you’re going to be replacing the tensioner and belt anyway, might as well replace the pulley while you’re there too. YMMV.
Having said that, I’m sure there’s way more seat of the pants feel benefit to going to lightweight wheels and brake rotors. Both of those will net 25-30lbs off of the unsprung weight of the car - which is well, huge.