I'll toss my 2 cents in: Since you don't know his vehicle, & you want him to get a winch he'll be happy with, you could give him a handmade card/gift certificate type thing that says "Good for one winch of your choice... etc."
I know that may seem a bit tacky, but it would also avoid getting the wrong thing & having him be disappointed or him having to pretend he loves it if he doesn't. I'm not sure if any vendors actually offer gift certifacates, but you might check. I've had very good service from Low Range Off-Road in particular, maybe give them a shout & see. (Hope this didn't come too late, since the big day is only 9 days away.) Zomg... 9 days!! I'm never ready!!
Hth,
Fuzz