Heres what I did to my 98 MTN SRX. 4" is your number. 144-136=8 x .5 = 4.all the suspension mounts move back 4". front of "w"arm back 4 and down 3/8. should end up right behind steering hoop brackets where your feet go. center mount back 4, down 5/8. rear mount back 4, down 1 1/4+. if you have access to 1/4" aluminum, i make my drop brackets 3 1/2 by 9 1/2, radius the corners and mount with 5/16 button head allens with whizlock nuts x 3 per plate, suspension hole in center. i use 1/8 plate to strengthen the 2 forward mounting points, and rivet on the 1/8. helpful hint: use a speed square inside the tunnel for layout. be damn sure all new holes are equal side to side, front to back. order a transfer enhancement kit from mtn perf. A fellow TY member gave me this info. No rail extensions. My sled loves to wheelie.