i have a 04 rev 800 144 that i swapped to a 151 challnger lite. i did a 3.5 inch set back and had to install 9 tooth extroverts so the track would fit. stock was 10 tooth with the 144 track. The gearing is 19/45 stock. will i have to change this with the longer track and the 9 tooth extrovert driver. is ther anyone who has done this? did u have to put a tunnel extension on? if so where did you get the 144 to 151 tunnel extension?Thanks so much for any help.