the timing chain comes as a complete kit, every part is replaced including the guides, tensioner, chain, cogs and the oil jet - even the bolts are new :lol:
mpg depends on driving conditions as usual, around town @ 25 mpg, on a run @ 40 mpg dunno..
the only other thing to keep an eye on is the oil level, the z22se doesn't like to be run low (off the dipstick) but that's basic maintenance on any car 🙂