I switched my '88 300TE over to Redline Synthetic ATF when I bought it (it had 67k, and now has 145k) and the gain I felt most obviously was improved cold-weather shifting. Same story with my brother-in-law, who converted his '88 300TE at 100k, and it now has something like 250-260k. He noticed the same thing. Neither uses any fluid, and mine shifts as well as when I got it. Now, my bro-in-law's tranny appeared to be getting tired 150k ago, but the Redline seems to have at least slowed his trany's demise.
Hope this helps...good luck!