Two years ago I changed for shorter cranks.
My previous set was 50-39-30 with 165mm cranks (BB included)
I used it for appr. 1500 miles (never in wet conditions)
$150 +shipping OBO
+1 wait
I'm used to ride my Silvio 2 on rollers, that is not as static as a trainer. It requires some concentration to stay on the rollers and coasting is not possible. Riding on the road is very different.
An other new product is showing up. Looks really interresting.
https://www.kickstarter.com/projects/934648866/urbanx-convert-any-bike-to-an-electric-bike-in-60