As has been mentioned here before, CASA has not all of a sudden mandated the Cessna SID inspections; they have merely provided guidance material that points out that the existing regulatory structure has always required compliance.
They (CASA) have gone the extra mile and extended the compliance period.
In any case inspecting and ensuring that said aircraft is airworthy should not be a matter of is it mandatory on not, it should be a matter of common scene or should we say professionalism.
I have been involved in several SIDS (as both an A/C owner and a LAME) and The “inspection” component of the SID on the 100/200 series Cessna’s is going to take somewhere between 80-120 man hours (Say $8,000 to $12,000) which is about the same cost as a reasonable funeral – I chose the SID over the funeral.
The repairs that may be required can be extensive. And the fact that defects may be found and that repairs may be required should not be an excuse to look at every way out of doing the actual inspections.
Of course the repairs required as a result of defects found and their possible cost is always the big mystery, however these repairs (or retiring the aircraft from service) should be carried out with or without a SID requirement.
Many aircraft owners and operators actually lack the funds to own their aircraft and when discussing the SID subject they comment with their pocket rather than their brain, considering that the 100/200 series SID was first published about 2 years ago everyone should already be on top of this.
The action to take now is just do it,
1st get a copy of the Manual, or more specifically the SID section, read it and take the time to understand it.
As the owner you are responsible for the maintenance of the aircraft, so manage the job, much like you might manage a building project, in the process be respectful of the LAME / Workshops obligations at the same time. To keep costs contained set boundaries, and request quotes for specific items as they pop up.
Talk to your preferred workshop and LAME, communication is key.
Jointly work out which inspections are most likely to present issues on your aircraft. By issues I mean things that might cause the aircraft to be uneconomical to continue. It would be a shame to find that something big required replacement/repair on the last inspection after everything else had been attended to.
Plan to phase in individual inspection operations or groups of inspections, perhaps fitting them in with other scheduled maintenance, and going from potentially worst to easiest. I.e. “At this inspection, I would like to include Cessna inspection operation 3, 5, 11, and 14 (randomly chosen numbers)”
Aircraft owners are funny animals, and for many aircraft ownership is some sort of status symbol, as well as a play thing. Its not anywhere near as satisfying striding into the aero club and telling your peers to come out and look at your new R/H wing spar cap than it is to get them to look at your new Garmin panel or leather upholstery, but at least you will be alive to drink with them.
By phasing in items over the new extended compliance interval this will ease the initial large cost burden, and hopefully by the compliance date you can have a completely compliance aircraft
As for the horror stories of what has been found, perhaps some photos would be a good way to show what is actually being found ?