Prepare for some info young grasshopper. If the Des Plaines listed under your avatar is Des Plaines, IL then I would suggest doing business with Protege Garage since they're damn near local to you. Even if you live across the country I still recommend doing business with them because they have an excellent reputation. There are a few other sites listed around various sections of these forums that can point you to them.
As for the parts and why you should get them, the stock rear motor mount has soft rubber bushings to reduce as many vibrations as possible. Unfortunately, this is accomplished by allowing the engine to flop around under the hood like a fish out of water (well, not THAT bad but still sloppy). The upgraded motor mount is either a urethane or denser rubber with a more substantial metal frame to help hold the engine where it is meant to be while driving. It really helps to eliminate those rough feeling shifts while accelerating since everything is lined up. You may feel a slight increase in vibration since the engine is now more securely attached to the car, but it's mild at worst. Most people only seem to notice it when the AC is on and generally only feel it in the steering wheel, it doesn't make your car feel like it's falling apart or anything terrible like that. I don't recommend anything over about 70 durometer stiffness since those have a tendency to transfer more vibrations.
I have not replaced my shifter bushings yet since I plan to do them with my short shifter when I start interior upgrades this spring. These replace the soft bushings under the shifter base plate (where the shifter attaches to the car, have to take out part of the center console to get at it) and reduce some of the unnecessary play in the shifter. The bushings are metal instead of rubber, or whatever soft compound they stuck under there, and are around $20-30 for the set... a worthy upgrade. Hope that helps some.
