I used the 3020R-30gr with the AH sliders on my 2013GT, I forget where I ordered them from but I did mine at the same time I did belt replacement (don't get the cheap version belt, they WILL NOT last), order the Mitsuboshi belt for around $110.00, mine came from Carpimoto in Italy if I recall. The sliders help a little in leaving stopped, REALLY wake up the mid-range and add 1 or 2 miles per hour to top end (they tell me) without much loss of economy. There are write ups in this forum that are very helpful, include a tool list and parts list to have on hand and helpful tips on how to reach the hidden screw and other quirks, it's a lot of work to replace the sliders, not too difficult, just involved and it's the same basic job to replace the belt that should go to 20,000 miles. Just a heads up that you may want to gather parts and tools and do replacement at 20,000, there is a noticeable improvement in accelerating and it may be worth the extra work to enjoy that, different strokes, different folks....