[gjm120]

My two cents worth...

You probably won't be real happy with that setup for a few reasons. One is quality is maybe not up to a high standard. Even if you're willing to take a chance on quality, your car may end up sitting very low. If the assembly is a one size fits all (i.e. 128i coupe to 135i E88) the springs may be too soft for a car as heavy as yours.

If your springs are in good condition (you don't live in the snow belt where roads are salted often) an option would be buy bilstein B4's and use your existing springs. In that case you should renew the mounting hardware.
This will certainly be more expensive than the Gabriel assemblies. It's just a matter of how much you want to spend vs taking a chance on the Gabriels.

If you do the Gabriel's - definitely get an alignment. If you go with a Bilstein or similar option, it's more of a probably yes.