Below is a copied reply from another thread recently started. I'd like to add this comment up front. 8-1/4 suregrips are available new at very reasonable prices.
The 8-1/4 gets a bad rap due to the size and C-clips. While C-clips can fail, it is when there under abuse there limitations arise. If the car is going to spend a lot of time with slicks and at the track, something larger may be a good move. Normal and occasional spirited driving is fine.
I have not noticed a shortage of components or selection of ratios. These rear can hold 400HP all day long. While the 8-3/4 is a much more stout part, the price is reflected.
No matter what rear you use, there is something some one could point at as a short coming.
What is the intended power level?huh