Grease car conversion for '02 dodge ram 2500

I would like some opinions on the “Grease Car” conversion. I have an '02 Dodge Ram 2500 and am considering it. It’s expensive and am worried about it really working, and the long term effects on the engine. It’s supposed to be relatively easy to install yourself. Does anyone have any experience? Though I live in Texas, I like to travel to the mountains. Is it really functional at higher altitudes and lower temps?

Any input welcome!

Thank you,

Kendra Mueller