Yeah, I used the Nel Lusso from Walmart, the way it is right now, does not go fast at all. The bike is very heavy after all the added stuff. It has a 50 tooth sprocket. This one goes about 15-18 Mph. Didn't use any special engine, just used the best deal 66cc engine kit on eBay at the time. eBay kits are a real gamble though, as I soon found out from buying more engine kits from there. Even tho they all look the same, the quality isn't the same , so be careful.
As far as the fenders go, They are either safe or they're not. There is no in-between. No gray area so to speak. And I don't think I want to keep them around my bike to find out... As far as access, haven't done it yet, buttttttt I'm pretty sure you can take the front fender off without have to take the wheel off.But You do have to take your rear wheel off to take that back fender off.