Ok, I have 12,500 0n my Heritage. I switched to Syn3 at the first change due to dealer recommendation. At 2,000 miles I switched to Mobil 1 V-twin in all three holes and found a noticeable improvement and a 20 degree engine temp drop. Since the first service, I have changed engine oil another three times in the 12,000 miles and the primary and tranny twice. Yesterday, I put in the Spectro Platinum tranny 75/140 and was hoping for some kind of noticeable improvement, but really had none. To be honest, I didn't have any issues with the Mobile 1 20w50. Shifting was smooth and quiet. When I drained out the Mobil 1 out of the tranny, the color was very good, also very clean. Only a very thin sheen of metal on the magnet and none in the drained oil that I could see at all. Stuff looked new and had 5,000 miles on it. I was a bit surprised how thin the Spectro was when I poured it in. I have the GL5 red variety, so should be the correct stuff, just seemed thin. At $16.50 a quart, I hope it was worth it, but we'll have to see. Rode 200 miles yesterday. The only improvement that I could honestly detect was that it did seem to downshift a little smoother.