A couple of weeks ago I had the opportunity to attend a GTS driver fitting here in AZ at Mc Cormick Ranch Titleist fitting center. As a bit of an equipment nerd I was pretty familiar with the heads and a lot of shafts so I asked my fitter Ben to keep it as blind as possible. We went over my gamer (TM QI35 LS 9° / GD Tour AD XC-6X shaft), got some baseline data and off to work he went. As he worked his way through the GTS 2,3, and 4 we discussed the data and what I felt. I totally let him guide the process and build up of the club. The result (average) was + 15 yds carry & total, +25' PH, and a large decrease in dispersion. I had a preconceived notion that I would be fit into a GTS3 - 10° with a Tensei Blue 60g S.. AND I was way off. Final fit GTS4 - 8° D-3 w/ 8g H2 and 7g rear weights, GD Tour AD VF-5 R1 shaft.
Did some sim testing once I received it and after working out my own personal swing issues with both drivers The GTS4 average was better in all categories - spin, launch, carry, total, dispersion. Put it into play yesterday and it was the best driving game I have had ever. Average drive 261 yds 11/13 FH, one miss was left rough and playable (par) and the other miss was a miss hit sky ball that the desert ate (took a drop and a double).
So far I really like what I am seeing from the GTS4!