We have a men's fashion thread—stop making me read this one.
Trench coats are flashy as fuck, and as with everything else flashy, you either pull it off completely and look like a dapper catwalk model, or you look like a titanic douche; there is no middle ground. I would strongly recommend stopping in a b&m, wear something nice and try before you buy—ideally bringing along someone honest with some sense, but I suspect you'll know immediately if the look is for you or not.