many retail outlets sell clutch kits for about that price. As for labor and everything, the last clutch I had installed ran me about $650 for parts and labor. Clutches are pretty universal, so you may not find it very cost effective to go to a specialty shop (i.e BMW only), but I'd still recommend going to a european specialist.
As for the type of clutch, Sachs is OE for BMW and the regular kit is more than sufficient. Unless you have engine mods that put your HP over 275-300, you won't really need anything more heavy duty...it'd be overkill.