So I decided to do a full flush of my GS. I put about 2000 miles on it while doing all of this and ended by doing a 700 mile road trip. Here's what happened...
Fuel System - So every so often, I would get some sort of fuel starvation where I would loose power but if I punched the gas pedal, it would come right back. This usually happened on the freeway when when I was going at a constant speed (kinda odd). So right off the bat, I ran about about three tanks worth of Chevron 91 gas w/Redline SI-1 to clean out the fuel injectors (and then stuck with Chevron 91 for the rest of the way). Seems to have worked as that problem hasn't surfaced since. On my road trip over the holidays (700 miles, mostly highway), it never happened and I even tried to induce it...so I'm going to call success on this one.
Transmission - Just before my road tip, I also did full trans flush using Valvoline MaxLife and then added Lubegard ATF Protectant...WHAT A DIFFERENCE. It felt like I had a brand new transmission! I mean the transmission wasn't horrible before, it had a a rare touch of "clunkiness" every so often and it felt like I wasn't getting full power to the ground (maybe slippage?) After the change, all that went away and the transmission felt INCREDIBLY smooth and full power was restored....incredible difference.
Engine - When I first started driving the car again, I did a motor oil "flush" of sorts. I did a $17 "coupon" oil change using Kendall Synthetic Blend with a quart of MMO and whatever filter they put on there. I clocked about 2000 miles on it and then changed the motor oil to Pennzoil Ultra (5W30) with a standard size Mobil 1 (M1-102) filter. I don't know if the Kendall Syn Blend/MMO thing did anything (oil/MMO mix came out pretty clean looking) but the end result with Pennzoil Ultra seems to be pretty good. Engine is smooth and quiet.
Tires - So I ended up buying some 17" OEM wheels for this car (I originally bought it with OEM 16" wheels from the dealer). The tires that came on the 17's were pretty shot so I bought some new Kumho Ecsta LX Platinum (235/45) and I have to say, they are VERY good. Since purchasing the tires, I've put 1000 miles on them with half of that being in rain. They grip very well (wet or dry)...they're very smooth and also very quiet. Definitely would recommend them for general passenger car type usage. Pretty inexpensive too.
Conclusion - I have to say, it was a pleasure to drive this car again. It literally felt like a new car. Even my cousin and a friend of mine (in different instances) asked me how old the car was. They couldn't believe that a decade old car could drive so smoothly and so quietly.
I also wanted to thank all the folks in this thread and the forum in general. I have learned A LOT here!