Folks with the 1800's seem to go for the full Traxxion upgrade. It's cost is about $2,500 for a full install. For me, I don't put that many miles or ride that hard, so the stock suspension works for me. If I were to upgrade, I would probably choose Progressive. They seem to have a reputation.
I agree with Two Wheel Wing, The Gold Wing suspension will do anything I ask it to do, It will takes the twisties as fast as I want to go. Progressive have been around for many many years, Traxxion is fairly new and very expensive. Everyone that has the conversion done has nothing but good to say about it, but what would you say after you spent $2500 on something????? Also I have heard of many that after about 40 or 50,000 miles the rear Traxxion shock has to be rebuilt.
I would go for a spring stiffer than stock and delete the anti-dive. IMO, spending extra money on cartridge forks is overkill unless you plan on pushing the suspension (i.e. riding fast on bumpy surfaces). I have cartridge forks in my track bikes but not in my Wing. I went with the heaviest springs (race tech 1.2 kg) and 15 wt fork oil and the bike feels much more planted. However, the ride is slightly harsher. If you wish a more comfortable/compliant ride, use softer springs. The switch to 15 wt oil made a big difference in front end feel.