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Last winter I completed all the Phase 1 flight testing cards before I installed VGs. The only flight tests I redid after installation were the full stall series and landing and takeoff distances which all definitely imrpoved. I have wondered how the VGs might impact other speeds such as Vx, Vy, and best glide. Needing to complete my Aircraft Operating Handbook, I decided it was time to redo the climb and glide speed tests. Early January provided a high pressure system with very still air for a few days. Winds aloft ranged from calm to 5kt. There was no detectable lift or sink flying early in the cold mornings. I spent three hours over two days testing at 5kt intervals. Testing was done at 2400#s 17.6" CG. Interestingly Vy and Vg both decreased, Vg from 75 to 70. Vy from 65 to 62. Climb rate at 60 and 65kts was within 10 fpm so I tested at 62 and it was 25 fpm higher. Vx remained the same at 55k. I feel that these were accurate results, the air was very stable and I was able to hold the speed +/- 1kt. I feel like the results were quite a bit more reliable than my earlier testing which was done with less stable air and I had more trouble holding the exact speed. Did the VGs change Vy and Vg? Don't have enough information to know, may have just been better testing. I found that flysto.net provided more accurate altitude numbers at 1 second intervals than I was able to record as the timer hit 60 seconds.