Hi, as per title, plan to do top overhaul on my wira 4g13 MMC injection. would like to enquire about parts n process involve during top overhaul. My car got leaking for a while now, so instead of changing the gasket only, I prefer to make it one time job. Not interested in full overhaul/engine rebuiding as the cost might as well buying new engine/car dp. Parts: 1) Head gasket (cld be normal or metal one) 2) Valve seal 3) Valve cover gasket 4) Valve guide, valve seat (may change if u plan to keep it longer) 5) Intake manifold gasket 6) Head bolts (old one tend to stretch) 7) Other cheap2 oil seal and gasket (oil sump gasket, crankshaft oil seal) too many seal, even foreman not know the name, lol. but important to know where it is located. Open up a little bit further, u can also replace ur piston ring or conrod bearing as these things also has its wear and tear. You are going to full overhaul already. Process 1) Head skimming (good time to skim it, as long as within manufacturers limit) 2) valve grinding (to keep good sealing between valve surface and port hole for good compression) 3) Wash parts with petrol (esp parts when u open rocker arm cover 4) Cleaning/ decarbonise parts (piston head, intake manifold etc) most cheap overhaul w/shop will skip (3) and (4). 5) You can also opt for Port and Polish while you at it. (better result if u plan to do engine mods like hi-cam, etc) This is also a good time to change other parts to minimise work, like water pipe, water bypass hose, belting, water pump etc if they need to change. Also a good time to flush ur rusted radiator. check if there is any leakage too. As for the parts part, what else that could help in engine performance and high wear and tear rate? piston, valve itself? Thing is i plan to buy the necessary performance part myself, any part and brand to recommend? Not all workshop capable of doing above process, so they ll sub it to machinist, hence higher cost. Those process might need professional touch, at least for me. If u happen to do or have recommendation of such workshop, u can list it here also. Think any engine will share more or less of above information. So please share your experience!