You should find another shop.. I'm guessing you're not super-handy and you found the best 'European' indy shop because it's your new baby, but I'm sure a job like this is regular stuff any decent indy can manage for a quarter of the cost. You should buy the parts yourself and pay the shop for just labor, supplies and incidentals. Clutch kits shouldn't cost more than 5-600 tops, and 5-6 hours of labor at $80-100 tops.. Just a very approximate ballpark guess without knowing exact part/labor estimates, but I can't be too far off.
E92 convert. BMW Fanatic.