I added a fork brace recently and it certainly helps the "noodley" feel on tight parking lot U-turns. If you did nothing else, that will probably fix your specific problem. Although I got lucky and the one piece brace did not bind my forks (like everyone on this boards warns against), I would recommend that you get a multi-piece brace that can be adjusted to match the exact spacing of your forks. Can't remember which brands are recommened but you can search this board for that answer using "fork brace" as your search criteria (I'm not going to do all the work for you).
If that does not provide enough improvement for you, I would suggest you try the Race-Tech (R/T) Gold Cartridge emulators. I installed this kit on both my 1989 GL-1500 and my 2005 GL-1800A (ABS but nothing else). On my 1989, I would experience a corkscrew twisting affect around the longitudinal axis of the bike (think of a line drawn from between the headlights through the center of the bike to the brake lights) whenever I tore through a high speed downhill sweeping turn and a mid corner bump upset the suspension. Not sure why the R/T upgrade fixed that problem but I never had it happen again (same turn, same speed) after the upgrade. My thought was that the R/T upgrade with stiffer springs brought the front suspension up off the bottom of its travel so it was better able to absorb road shock and bumps. The other thing the R/T upgrade did for me was to keep the front tire more in contact with the road whenever I hit a pothole. Before the R/T upgrade, when I was leaned over in a corner and hit a pothole, the tire would bounce out of the hole and skitter sideways before regaining traction (very unnerving). After the R/T upgrade, it felt like the tire was never out of contact with the road and the sideways skittering was non-existant. This allowed me to significantly improve my confidence level and take corners on marginal pavement at much higher speeds.
You can install the R/T upgrade yourself and the cost was less than $400 when I did the upgrade on my 2005 about two years ago. That included new seals, bushings, copper washers, fluid, and Race-Tech Gold Cartridge emulator kit. Do not start the upgrade unless you have all the other normal fork rebuild parts on hand. If you end up not needing new bushings, you just use them the next time you tear into the forks.
I recommend that you start the upgrade on Saturday AM and take breaks if you start getting flustered or irritated with your progress. Read all the instructions the night before you plan the project so you have a clear understanding of each step before you have to try to implement it. I will tell you up front that the instuctions are pretty crappy. They were written by the owner and he really knows his stuff but they are written for a professional motorcycle mechanic and not the typical Gold Wing ower.
The first time I put in the R/T kit it took me 6 hours over two days with someone helping me, mainly to cross check my work. The second R/T upgrade took me about 4 hours and I completed it in 1 day.
