Thanks for the replies for far. I think the nature of situation here means it's can't be something he can be alerted to unless it's subtly asking questions. Also, it's a gift from his wife, not from the cycling friends. Closest quality fitter to us is a 3-4 hr drive so that's probably out.
Yeah, unless he's specifically requested an item, I wouldn't go buy him something. We're all fussy about our gear! But maybe the wife could drop a hint? "hey, if you were to get one item to make your bike faster, what would it be?" And as a gift, it needn't be the most cost-effective performance gain, it would be about what makes him the happiest.