Just installed the 60 volt mod from Electric Motorsport on my EVT 4000e. No magic smoke escaped, Woo-Hoo!
Best. Upgrade. Ever.
I only had time for a short test ride, and the forecast calls for rain tomorrow, so I won't have any objective GPS data until Sunday. Scooter speedo showed 42 MPH at top speed. Better acceleration -- Economy mode is now peppier than 48 volt Power mode. Better hill climbing. I hardly notice the extra battery weight when riding. I am a VERY happy camper.
I installed the 60 volt mod this afternoon without removing the body plastics. Easier than installing PowerCheqs. Now the bike performs like I always expected it to. I should be able to keep up with my wife's Honda Metropolitan now. I did 10 miles of fast take off, full power, stop and go riding and it was still on the top green LED when I got home. That should mean I've got a good bit more range with that extra EB-50.
I'll post more when I get a chance to gather some good numbers with the GPS.