I have a 2010 Vector. 136". Was wondering if there was a way, or if it's even possible to fit a longer track under it. Something like a 144" like what the Apex has.

Check out tracksusa.com - they have rail extension kits. You bolt them onto the back of the rails to move the rear axle back and then put on a longer track. I am not sure about the vector but a lot of sleds you have to modify the tunnel as well to move the snow flap back behind the longer track. Also a lot of times you will have to change the gearing. You are pushing a bigger load because the track is larger and heavier (and pushing more snow). Usually drop a couple of teeth on the upper gear - you may need a shorter chain as well depending on how many teeth you drop and much slack you already have. Your dealer should be able to look up what size chain you need for the gear combination you settle on.

Good Luck!
dave