Troy Hamon wrote:....... some things that need the super-duper FAA okey-dokey stamp to be installed in a FAR certificated airplane can be installed as minor modifications in CAR-3 airplanes, especially panel stuff...(within reason...tread carefully...read the actual regs...)............

Some things are kind of at the discretion of your IA, and what he feels comfortable signing off on as a "minor" versus what he considers a major alteration. Not so much that things are unaddressed by the regs, but that the regs can be somewhat subject to interpretation.
A good IA is a godsend & a necessity for owning an airplane, esp if you're on a budget. Not that I advocate anyone skirting the rules, but some common sense (pretty rare these days) needs to be applied. Someone who is too "by the book" can break you. I know of one IA in particular who seems to quite regularly make a mountain out of a molehill, esp regarding paperwork, and who's caused his customers no small amount of grief IMHO mainly by trying to show off how smart he is & how well he knows the regs. If it was me I would drop him like a hot potatoe, but he seems to have some of them buffaloed. The sad part is that he's not even that good (or thorough) of a mechanic.