I'm actually making an emiya shirou wig for Anime Boston. If you haven't spiked a wig before It can be a little challenging, If you have a friend that can help you I'd say get a wig and have fun. Cause two minds are better than one :P
If you do spike the wig just remember you'll want nice big spikes with a soild dab of Got2BGlued spiking gel at the end, not covering the whole spike. (other wise they get heavy and look wired. xD) and you'll probably want to get a can of the Got2B freeze spray for the end.
Alsooooo If you're bringing kiritsugu to Anime Boston 2013 pleaseeeee hunt me down.
I'll be Illya with Shirou's dismembered body. xD
-edit- Also I will never use the Cosplay.com store ever again, I've never had a good experiance with them. I know a few people that said they were okay, but I'm leery of them now. Arda wigs, and amphigory I've had good luck, but I tend to use Ebay. Out of 20+ wigs I've bought of of ebay, only one did I get screwed on :P But I don't buy expensive wigs so it wasn't terrible. :P Here's one I found that seems to be good.
It's looks puffy so styling it shouldn't be as bad as if you got a 40" inch black wig and worked from that.