Just to clairify... some people use the term "motor mount" as interchangeable with "transaxle mount" and "anti-roll resistor". I'm not sure which ones you're asking about. But yes, generally fresher stock units are better than older/shredding units and urethane does help, but some might be more important than others in helping put power on the ground and reducing wheel hop, with the roll resistors being the big players on that topic.
As you move past urethane front resistor inserts and into solid urethane anti-roll resistors, expect your NVH (noise vibration hum) to greatly increase and your CD player might skip more. Pole120 can set you up if you're looking into solid urethane roll resistors.
Less wheel hop should be less dangerous for a stock differential while doing drag launches, but stock axles are still a concern if you have enough power/traction to threaten them. On a 2.5L without drag radials, the axles are at much lower risk than a stock diff.
I expect others will add a bunch to my general comments here.
