I had the same dilemma James. It’s an expensive upgrade for 25hp. There are others tuners who will give you more for less £££. Even if you are out of warranty though that reassurance of the fact ford was supportive of the upgrade is something to consider.
Like you, I waited for a while ‘as stock’ before I considered it and I think this is the way to go as you are more tuned in to any differences.
The ‘can you feel the difference’ issue has been discussed a lot. For me there is certainly more mid range punch and you definitely get more turbo / dump sound. I’ve only done a couple of launches but I really felt the difference then.
I waited till Ford Fair and got it at something like £850ish I think (significantly cheaper anyway) and fitted at Mountune HQ.
I don’t regret it.
NB FPM375