We used these in my fire service for stabilizing vehicles. They are great if used the way they are intended. Ours ran off the exhaust, not compressed air. Other services used those, but I have had no experience with them. I would not think that an aftermaket tip would create any problem, although I can't be certain about this model. Our models fit over a 6 inch exhaust, and could fit much smaller if needed. (I think I put it on my old chevy truck once)

01SalsaXterra, When I used these there was no problem with the exhaust being too hot, or any signs of potential melting. Although we didn't run them for extended periods of time. I wouldn't recommend trying that either.

These things were extremely useful when used in the right circumstances.

Biggest advantages: Jacks very quickly, and high. (We even stacked 2 once, not recommended btw) If you need to get higher, make a base out of some stacked 4x4 blocks. Provides flotation for softer jacking surfaces. The few times we got to use these off pavement (on road shoulders and ditches) they worked quite well. I can't say as we ever tried them in sand or mud, but I imagine they'd work great in those situations.

Big disadvantages: Must keep engine running, and under some circumstances had to keep engine at a high idle. A blowout, or coming loose from the exhaust will drop a vehicle in a hurry.

If you plan on using something like this for lifting your vehicle, and need it to be suspended for an extended amount of time, use cribbing or something to rest under the frame. Although I know it's not too practical for most, we carried a few 4x4 wood blocks, cut to about 2 feet long, to stack and put under the frame.

As for that, I have no idea how the use affected the engine in the short term or the long term. All I know is we saw no change in engine characteristics, although hooking it to a fire truck is a bit different than the X.

Hope this helps.