I have a 121" track and want to stretch it to 136" using Tracks USA Kit with rail extensions, tunnel extensions and 1 1/4 " ripsaw track. These are my questions: Will it hurt my gas mileage (currently 15-16 1/2mpg)? Has anyone had any problems with overheating with this set up? Do I need to make any gear changes? Do I need any extra idler wheels? Will the ride be even better with the longer track and the M-10? Thanks for any input you have!