What size compressor do you have?
What media will you primarily use?
Do you want a gun with a trigger, or just a nozzle with a foot pedal?
The pedal controlled nozzles are much smaller, this might free up just enough space to let you blast a bigger item if your cabinet is on the small side. You might also find the nozzle to be easier to control and cause less hand fatigue.
I briefly looked at the TP tools stuff, I wouldn't consider their prices on replacement/upgrade parts a good deal by any means. Grainger has equivalent stuff for less and that is at their catalog price.
Get a tungsten carbide or boron carbide nozzle.