I have replaced the drive springs, purchased from Mark , on my coupe,it's a very straight forward job, while my car has the electrical regulators , they are basically similar to the manual unit.
I have had a look at the parts manual , the coupe and spider regulators have different part numbers, but I wonder why ?
The spyder upper door frame is I think the only difference between the two ! As a result the glass on the spyder will be slightly smaller, requiring the glide channel to be in a slightly different place perhaps clashing with the location of the fixing point of the coupe regulator , maybe a slight modification of the fixing bracket might be possible, or if you have a good coupe unit it would be simple enough to swap the drive spring from one to the other.
Best of luck