I have seen now quite some "perfectly stored and always well maintained" Cessnas that I do not believe that statement first sight. There are some sweet areas you won't have recognized before and there probably will be an issue somewhere.
If your bird is really well, then the SID inspection is not a big deal - if you don't do it as a celebration event, but add the few things to each standard inspection 50/100/200 where it fits. By this the SID will take several inspections, but the additional costs are in the low 4-digits in sum (our training 152 came back from Czech with a 2500 bill for the SID event and minor work found, adding the labor to the ordinary inspection was not possible due to - we ****** up the schedule and needed it in short term, would have been less). I say, worth the money.
If your SID turns out to be expensive, there are two possibilities. You have been ripped off, or there were serious issues with your aircraft. The first is really bad, so avoid it, but the second could safe your life sometimes.