That info is correct yet incorrect at the same time. There was the RS= non turbo, RS-turbo (come badged just as an RS, like mine was) = turbo no intercooler, and RS-x= turbo intercooled. I have original DR30 brochures at home.
That hatch has had a facelift, I know the bloke that bought his old DR shell. I believe it had a decent engine bay fire.
My mates DR should be back on the road soon with a fresh motor after he popped it. It's running a GT30 with a few other goodies, it's bright green you wont miss it thats for sure.