Respectfully, some of you guys are really overthinking this. I’ve done this type of conversion many times, mostly on GP’s (4 or 5) and 2 RS3’s with no problems. The electronic e-units have been able to handle the extra motor with no problem. One thing you should do is inspect and/or clean/lube the power truck. I had two trucks that had hair (cat hair I assume) and steel wool. What a mess!! An alternative, if you want e-unit only, is Dallee Electronics. I’ve used their product many times with no issues.
Steve