The Lath motors will give you less speed and more torque. Also they are shorter then the MM' and alow for easier design of your 4 links. Also, if you use the mm's you should really gear down to a 9tooth pinion which means you need to get adjustable motor mounts...

There is no point in runnin 14.4v. You just add a lot of weight.
The super Rooster is a great ESC!

Also the Lath motors pull less draw off of your esc extending battery life. 2 55's = 27.5 draw on the esc and 2 mm's (22t) = 11T draw so you can over heat eaisier.

If you are having problems with your servos halting your movement then just add a 4 or 5 small cell RX pack and you will see a huge improvement in your streering power and stalling. I use an inexpensive ESC so I need the extra RX batt. But with the Rooster, you may not need it... Hope that helps.... And for chassis, Why not build your own? It's fn and very rewarding to be able to say you actually made your rig. G.