Hi, I just purchased a 450L for the wife, wanted an automatic Bike for her because we go to the dunes a lot. Thought the 450L would be powerful enough and I didnt consider the weight of the bike. so went on the dunes last week, reduced the pressure on the tires to get better grip, was super disappointed at how weak the bike was especially going up hill(not a big hill). I was wondering if there was any Upgrade parts that are available to increase the overall power of this model?