Nice pics mate. Its good to see the young fella out there with you. My dad got us out there when we were young and have done it a further 4 times. Three in cars and once on motorbikes. Some of my best memories are out there. You should of being able to get up Big Red with your setup, owell next...
Tony the new STX models are V6 and the old STX is now the ST which is still the four pot. If you want the leather then 550 it is. Or get the STX and put the money you saved towards mods like suspension, bullbar etc.
Bugger, sounds like you have a dead one on your hands. Hopefully it didnt break up and get into your engine. I wouldnt drive it anywhere until you have it sorted.