I've never had any of the above problems on either of mine or my 182 BUT.... I have heard of the air bag/seat belt thing before.

Above all the MOST important thing when it comes to buying a 172 is the Cam Belt/Aux and Tensioner/Dephaser pulley.

If the pulley fails it will strip the aux belt which will take out the cam belt and scrap the engine.

You can tell if its fucked as it rattles if you try and rattle it and whines like a power steering pump if its on its way out.

£300 to have changed, needs a special tool or engine out ( but can be done without either if you have small hands )

Dont be scared of 100K + cars my first 172 did 104k before its first track day and was still going strong at 114k when the pulley went and I sold it on.

Body is cheap french shit.
Interior is cheap french shit.

If you're tall then you may find the seats shit as they have low backs - I'm 5'10" and they take a bit of getting used to.

They go like a bastard, they need the nuts reving off them and corner like on rails....

Awesome bits of kit....

I will own another one soon.

Jakes top tip - find a boyd up kev chariot and rip do the numbers on the chav selling it - take all the crap off and enjoy.

Jake