I haven't seen alot with high hours, but I've seen alot that look like it! The smoke could be valve seals, or injectors. Remember, the duty cycle is way different than our trucks. I have seen quite a few that when I get in them, the throttle is 1/2 or farther open. Can you say "stupid shutdown"? The new ones with the foot pedal too are much more fun and operator friendly.
You don't want to retrofit hi-flow to your machine $ :{. It's another pump, valve, lines, etc. Hi-flow would be for milling heads and some snowblowers. Most attachments you need are regular flow. Auger, Hy-rams, grapple buckets, brooms, backhoe.
Pins aren't that bad, just like anything else, spray 'em, maybe heat 'em, swear alot!

Never-seize on assembly.
No problem on the crack thing! Sometimes they do it anyway, depends on the use and loading. The extra weight does make a big difference though. If you need extra weight, maybe add a bracket on the back, then put on suitcase weights when needed.
You're Welcome!
pete