I was looking through a couple of Mustang sites and i saw a few Mustangs with no spring insulators and some with stock bumpstops, how would this effect the drop of the car??? would a stock bumpstops not give the car as low of a drop as it should get??? and will not adding spring insulators lower the car more than it is supposed to be???

 

In your title you said "bumpsteer", but in your message you said "bumpstop". I'll assume you meant bumpstop...

You can take your spring isolators out. Although it is not recommended. The isolators are the thin barrier between the metal to metal contact of the springs & control arms. In ANY cars suspension, metal to metal contact is not optimal. Urethane isolators are the closest thing to metal to metal contact (stiff, non compliant material) without the drawbacks of noise issues, etc.

As far as the bumpstop... A bumpstop is located on the frame, right above the rear differential housing. It is ONLY used when the car bottoms out, or experiences a dip in the road. Usually people are hitting the bumpstop if their car is too low, and they do not have good shocks in the rear. You can get the Maximum Motorsports bumpstop (aka pinion snubber), which will allow for more clearance and more of a drop... This bumpstop replaces your tall factory bumpstop...

 

Actually the bumpstop is on the strut under the dust boot

Does this get switched over to the dspec strut during install? And do you reuse the factor dust boot? It has a metal washer at the top, the dspec is open with no washer