I'm far from a expert but i'd say with the stock motor no shimming req. but the turn buckle issue i'd go with the new era set. easy to adjust and they don't have the ability to pop off. really on the diff i have seen many diffs blown but has never blown one myself, i have always ran my car "Mt2" with a .28 in it and it's a 2 speed so the stuff is strong. i think if you try to keep the wheelspin down the diffs should be fine even with a bigger motor. i have never spun my car in circles because...... well it would eat it's self alive with the .28 cvd's,tires,2 speed tranny something would lockup and break ! while the car is new nothing should pop off after a while the turnbuckles will become a issue.