yeah just make sure they're aware you only want them to do labor. Some shops build their business around parts mark up, thats what Stealth is saying...so as long as they know up front you're supplying the parts, and they agree to do it, you're fine...
so...i'd say take your car, your 626 gear box, 2 new axle seals (rockauto or partsgeek should have those for cheap, as well as parts stores like Autozone), and 3 quarts of something like Red line MT-90...that should be all they'd need, and you'd only have to worry about labor on their end...They'll probably tell you your engine mounts are bad and things like that, but tell them you'll deal with that later on your own...especially if you're going to eventually be putting the MSP gear box back in...