What car are you running?
If it's running smoothly and feels right, the odds of significant valve problems seem rather low. If you've got lots of pressure in the exhaust, that argues against leaks. As for the comparison to the Camry, remember you've got significantly different engines in the two cars; just how different will be elucidated by the answer to my question above.
'97 SL500, 40th anniversary edition
'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)
SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)