I have a 2006 year Rans V-Rex. It was right before the cheaper LE came out. I have been riding it for two years now and have come across the following structural failures. Below is a pic of the bike.
#1 The seat
The first few months of riding my V-Rex I noticed that holes were being worn into the seat mesh. I found the solution was to double up the seat mesh to make it stronger. Below is a pic of the seat with holes in it.
#2 The seat stays
There are two metal tubes supporting the seat held in by allen bolts. The right side broke. I believe this could be dangerous and the design encourages breakage due to the cylander terminating about 1.5cm before the screw. Bad idea. I hacked off the end and redrilled a new hole, no further problems. Below is the side that I modified. I am referring to the black tube.
#3 Chain idler
There is a cheap plastic piece which keeps the chain from coming off the idler wheel. It broke off so I modified it with a ballpoint pen and bolt.
#4 The seat clamp
The seat clamp slides a lot and is tightened by two screws. Unfortunately, these two pathetic little screws screw in to plastic so when they strip out the clamp is useless. I believed they changed the design of this clamp so I will call and ask for a replacement.