As long as your engine is not consuming oil, leaking or emitting white smoke then it should not need an overhaul. You may want to get a compression test if you want just to assess the health of your engine just as well.

I agree with what jick.cejoco says on the intake; if you want to upgrade then you can look at getting a Simota tube from Banawe then a K&N filter. If not, get a replacement part for the cracked flexi tube of your Corolla intake and stick to the OEM filter. You can try inquiring with Toyorama at Banawe (near E. Rodriguez) or NGK parts. Check also with the CASA to compare prices or even walk around and see if you can find a surplus part.