1993 Toyota Corolla power of the engine

If the engine is overhauled can it perform like a new engine or not and what cause the crankshaft to have a rigge/damage. Can re-sized crankshaft can reduce the power of the engine or the engine can still maintain its powerfullness as like it was new. What can I do to impower my 1.6 engine for corolla twincam gli meaning is there other parts I should put on it to improve the power. And my gear box have a little bit problem to get on gears so I don't know what can be the cause of that. If the timing belt can cutted can it cause an engine knock on 1.6 engine or its a slimmy chances to have that knock. What can cause the engine knock and what indication can show me that the engine nearly to have that problem of knocking. What is differ the capacity of engine eg: 1.3 and 1.6 why differ cause other 1.3 engine are faster than other 1.6 engines so I want to know what is the difference between that. Can 1.6 engine can pull a laggage trailer which is not big and if its so what can be damaged if I pull a trailer which is not enough to be pulled. How long should the pistons rings take while in a good condition. If the engine use carbarator and other use injectors, which one have much more consumbtion of fuel and why if its so