$160? i'd rather save oh i dunno... $140 or so and get the stock unit from any of the 916 legacy bikes.
i don't care if the TPO unit's "twice as stiff" as the stock ducati one off the superbikes. if the stock unit from a 916, 748, 996 or 998 can support a bike with 20% more hp than my s4, it's strong enough for me. shoot... you'd have more than enough $$ left over for a used showa shock which i'd figure is a much more significant upgrade!
Stiffness is no issue, after all, it's pushing on a spring...and if it's actually twice as stiff as the OEM pushrod on my S4, I'll eat my Arai. It's not twice the cross sectional area, which is the only way it could be twice as stiff.
Strength isn't really an issue either, I've only heard of one guy here that bent his stocker, and that was on a mammoth New York pothole.
another thing the seller harps on is that the stock unit's cast. shoot... if you ever handled one (i made my bike itty bitty bits and had a chance to assess pretty much every part external to cylinder heads and crank), you'd see the machining marks. they're made from rods that are turned down on a lathe. again... if the stock bit's good enough for a bike with 120+ hp, it's good enough for me.