There's not much difference in size between the TSL and the Prodrive.
TSL GpN Vs Prodrive by
sbarnard69, on Flickr
TSL GpN Vs Prodrive by
sbarnard69, on Flickr
There is a difference in hardness between my head and the diff housing though
Head Vs Diff housing by
sbarnard69, on Flickr
Looks good and sounds even better
TSL GpN on Classic Impreza by
sbarnard69, on Flickr