Dunno about cheapest, but Neo Brothers were a lot cheaper than the dealer (about 1/3 of the price) and Euro Car Parts are around the same price if I remember. I couldn't find them on Elkparts, but they might be there somewhere - /john?
Good point, mutungi.
The ones I got from Neo Brothers had the same manufacturer's name on them as the originals and are standing up well to masses of abuse from my tuned Aero engine.
Well worth checking that you are getting the same stuff, but cheaper isn't always inferior. Just look at all the Saab parts you can get so much cheaper than from the dealer, both supplied by Saab and supplied by their own suppliers (e.g. Textar brake pads). Saab dealers have a different pricing model from most other outlets.
According to Euro Car Parts, they are different part numbers and different prices. However, you're only looking at £52 + Vat each for the 2.3, while they'll be around £160 each from the dealer. I think the ones ECP sell are the same ones I bought from Neo Bros. for my Aero (German manufacturer, but can't remember who), and hence the same as you'd get from the dealer.
Neo Brothers told me at the time that the 2.0 and 2.3 mounts were different. This might have changed in '94 when the B204 engine was introduced, but I'm pretty sure the mounts for the '90 2.0 are different from all the 2.3s.
There are two mounts (the "hydraulic" ones) on the right-hand side of the engine (looking from inside the car), one front and one rear, and a single rubber one at the other end, on the end of the transmission casing. i.e. three mountings in total underneath.
Other than that, the only other mounts that you might need to look at are the ones at either end of the engine tie-bar up top. These suffer a bit if the others fail (and vice-versa, which is why it's best to replace any failed mountings as soon as possible after you become aware of them).
The tranny mount is difficult to get hold of for an early manual (the only place I found was the abbott poly bush or specialist breakers). The early ones (-94?) are pressed into the casing and cannot be bought separately. I don't think you can even get it from Saab. Later models have a strap around the mount and a modified case so they may be available from saab. The one listed at eurocarparts is for the automatic only.