The 4G63 engine is world renowned for it’s excellent tuning potential. Fitted in various incarnations from the Evo 3 up to the 9, it is generally regarded as a strong proposition as standard. Many cars now run 50% more boost than standard without issue for tens of thousands of miles. However the standard blocks are not infallible, the cast conrods are relatively speaking quite thin, and it’s not uncommon to hear of rods exiting the block when owners run too much boost. Spare engines are relatively plentiful, but don’t buy blind. Ideally you need to see evidences of regular oil changes at the very least.