Traveler
You don't say which model 27 you have or if it already has a traveler and you just want to move it from the bridge deck in the cockpit to the cabintop.In any case a traveler, where ever it is is a sail control. It may help or hinder the ease of your sail adjustments, but it won't make the boat any faster. At best it may let you achieve the best trim more often. In my opinion, the 27 is too small to need a cabintop traveler; and cabintop travelers are slower to adjust than cockpit or bridge deck travelers.If you want to improve performance; better, newer, larger sails; improving the bottom finish; taking excess weight out of the boat will help as will a folding prop. Basically you'd neer to increase power and reduce drag.