Bullwings

So, the dealer is going to do a compression and leak down test for me. I can watch them set up the whole thing and run it and see the numbers.

I already know what i'm supposed to be looking for as far as numbers, but what're some possible mechnical motor problems that you can't see with this test? If all the results come out good, is there anything else to be worried about?

I test drove the car and tried to do as much as possible in the "used buyers guide." It's the third s2k that i've test driven and nothing stood out as feeling or sounding funny between the three. Is there anything else to be wary about - other than the dealer fudging things?