RE: 2006 GO 170 vs 185
What boom did you get (manufacturer/brand)? Perhaps I can look at one online and offer some suggestions to solve the "opening up" issue.
Some of the boom head clamps are quite sensitive to how/where you attach the uphaul.
If you move the uphaul attachment to the other side (from the side where the boom clamp handle "closes"), there is a lot less likelyhood of the uphaul line catching on the handle and opening the boom clamp mechanism.
If the deck on your new GO Roughskin (yes, many '06 GO customers have made this same complaint as it was never a problem on the older GO boards because they had all eva and no non-skid on the rails) feels "soft", I'd take the board straight back to the dealer and have them evaluate the "softness". Other than a slight "resilience" from the EVA layer, there should be no softness at all to the deck of your board.
But, you seem to have discovered the performance of the GO, and I can assure you that very soon, when you get the boom clamp issue rectified, you are going to find the board feels alot more stable and once moving gets solid as a rock.
You will soon be zipping around fully planing all the time.
Hope this helps,