i found that the ring issues affect both cg13 and cga3, probably just the longer stroke tbh
same goes for the crank bearings (more loading than the 1.0)
PCV valve tends to get full of oil residu.
The MAF is a weak point but you can swap it with a new one.
The carter filter in the airbox isnt swapped often and gets full of oil residu. Often overlooked btw.
Also check the linkage of the gearbox the first part where the linkage bolts to the gearbox. There is a swivelpoint and that tends to rust causing the swivelthingie to get stuck between. You can sand the rust off to make the gear change a lot easier.