I had a mongoose for 18 months, but in the last 4 months of ownership I suffered with replacement back boxes losing their baffles. I don't recommend Mongoose. Good warranty, but quality is xxxx.
I bought a Powerflow "Wheelbarrow" off of Oukie for £200 and wouldnt go back to Mongoose.
First time I saw that I thought it was a scam: "The picture of the system laid out on the cardboard is what you will receive. Please note that the tail pipes seen on Stoner Racing's car are not included."
From that it sounds like you will receive a picture. I assume that is not the case.
Killed 2 Mongooses (or is that Mongeese) in about a year, one the o/s hanger ripped out of the backbox and the other (about 5 months later) one of the tail pipes broke off and started flapping about in the breeze.
I've since realised that the cause of the breaks was a set of rumble strips (about 5 on one stretch of road) on the way to work.
I still think welding the hanger to the backbox is a bad design.