I've done about a dozen up-pipe replacements in the last 6 months....they get REAL tiring after a while. The funny part is that mine have been leaking for better than a year but I'm so busy with everyone else's junk (term of endearment) that I haven't wanted to even
look at my garbage.
In all seriousness, I would definitely transplant the Adrenaline. Your EGTs and towing performance with the AD injectors will be exceptional.
I believe that you would be happier with a minimum of 40 HP. 25 HP can be had for free on a cool day given the right atmospheric conditions. Besides, there is always "stock" if you can't maintain sub-1200 degree EGT with the 40 HP.....I however doubt there will be an issue.
Get it done!