Dale, as far as the differences in fans... The early TR6s had smaller, yellow fans. Later TR6s had larger 13 blade red fans. If your TR6 has the later fan, it was effectively upgraded to a larger fan capable of moving more air than the standard early fan. If your not overheating, the extra shroud around the fan won't do much, and what it helps with would only be noticed at idle. It may increase the efficiency of your cooling system slightly, but it would be a bunch of effort for very little, and in your case unnecessary gain. If you have the shroud forward of the radiator, the amount of air it directs through the radiator at speeds more than 25-30mph is more than the fan can pull through anyway. So over 30mph, the size of the fan and the shroud around the fan don't make much difference.