had a quick look over it this morning and i had to resolder the on off switch as the + and - were touching a few fiddles and the car wouldnt turn off, tidy little solder job later and its fixed.
not stopped the stuttering though. moved the aerial and this was to no avail. tweaked through the odd setting and still no change. you can feel it when driving.
but main time it happens in when idle IE no throttle.