Msd
 

My buddy has an 88 Mustang GT with the 5.0 in it and just pit a MSD ignition box in the car and says it boosted the responce time to hella.

what do you guys think about them??
and what 1 will fit my 91 motor? (DOHC)

It would take some messing with the distributer but it could be done, not sure if it needs the tach adapter to run to the computer either. Might just want to start with an upgraded coil. I loved the throttle response I got out of my camaro when I added the msd and the gas mileage improvement. I would stick with the MSD 6A, the SCI is the same thing just smaller and more expensive, and it will run hotter due to the smaller size.