what sort of suspension are you running? and what tire pressures?
I have an used Autotech mkIII hollow bar, I'd sell it to you cheap...shipping would be interesting.
For the previous chump car which was a 4cyl; we ran Mike Ogren's axles. He uses stronger cages, slightly smaller balls, and a quality grease. I am sure he can do the same for VR axles. Otherwise DSS makes them for the high HP drag guys.