We recently purchased a Momentum 21G Toy Hauler, and we love it, but there are a some annoying things that needed to be added/modified. Here's our list of mods so far, must-have's first: 1) Custom made support for rear awning. This is a must-have in our opinion, and one of the first things we did. The rear awning has no support at all, and any little wind could tear that thing off. Easy and cheap to make yourself. 2) Caulking around bathroom, shower, and kitchen floor. Obviously this should be done in the factory. Preventing water damage is critical. 3) For exterior water station, added a water collection pan with drain, plus caulked throughout the entire water station (more potential for water damage if not done). 4) Home-made venturi for generator exhaust. Bad design to put the exhaust right below the bedroom slide-out. You can make a home-made venturi cheaper than buying one. You would have to modify the one that can be purchased anyway to get it to work on a 21G. 5) Minimum 4 inch memory foam topper for bedroom - that is one hard mattress. 6) Add external storage 1: we added the Trailer Tray A-Frame Cargo Carrier from Stromberg, and put a large waterproof toolbox on top of that 7) Add external storage 2: screw peg board onto internal wall of tall external storage bin - really helps organize that space. 8) Add external storage 3: Future storage we will be add underneath the camper for awning supports, venturi, etc. 9) Attach hose to rain spout above passenger side tall external storage bin to reroute water - otherwise water drips on you while getting to storage, and could easily get into the storage compartment.
10) Custom tie-down system for dirt bike: It cost me $150 in materials, and a little labor to assemble it all. And this is to tie down 4 dirt bikes in two rows in our Momentum 21G. I like this system better than what "Bolt It On" came up with, which is way too expensive, requires you to purchase expensive add-ons for additional bikes, and still requires you to use tie-down straps on the front forks. 11) Rear and side cameras. You can get Furrion cameras added by the dealer, but they are more expensive than the Haloview MC7108 system, which is just as good 12) Main awning supports. Can be home-made from PVC pipe. They main awning seems to be fairly sturdy, but we can get high winds where we are at, and a new awning can be very expensive.
13) Added U-shaped brackets (with felt pads) and bungee cords to hold folded mattress in place when travelling. No need to drill or mount anything in your bedroom.
Pictures of all mods are here: