actually, for everything you are getting in that kit is seems like a good price. I'm sure it's more expensive than peicing the entire kit together by yourself, but this saves you time and hassle of trying to wheel and deal, as well as you will know the condition of the parts you are getting unlike taking a chance with someone's "like new" transmission off craigslist
I have done this swap before, Just go find a parts car or dig through some junkyards. get a good NEW clutch, spec or centerforce and a NEW good trans. You can get a TKO600 for like $1800, a little pricey but it will hold whatever you throw at it.