I don't want to dispel anyones advice here but I am 99% sure that the RS turbo boxes do have additional strengthening webs in. There was an article in either FF or Pf a few months back that was really good on the history..or if you want to try and find a company in Southport called Gearbox Exchange and reapir service (GEARS), it was that gut that wrote it.

If you really want it, Pm me and I can post you a photocopy.

ant