I use my LiquiVac when the oil is hot, and it causes the tube located at the junction to the storage unit to deform a little, but seems just fine. Done lots of changes on various MB's with it, and love the thing.
The way I figured it, the LiquiVac was half the cost of the labour of ONE oil change. So, I took a risk and evacuated hot oil.
If it takes using the LiquiVac/Topsider to have frequent oil changes, then do it. Otherwise, the tried, tested, and true method that Larry advocates is just fine.
1998 C230 "Black Betty"