I'm impressed and surprised the T5 lasted that long. Seems most or all of the Fords have abandoned the T5.

Are you going to submit an RCR to allow that toyota transmission? Hah.

1 minute google search came up with a t56 kit. https://www.bowlertransmissions.com/...-pump-upgrade/
Then here is how to do it. http://www.pozziracing.com/Bowler%20...il%20pump.html
But Mark Stielow says it's needed above 450 hp.

Maybe allow it for the T5 if that will keep them together-is it legal to put the T5 in a fourth gen?

Personally for the T56 I don't think it's needed. What kind of fluid are you running and how often are you changing it? Have you had it analyzed? I don't think it should break down at 250 but I'm certainly not the one to know.