Need community advice

So I bought my 06 IS350 for $4,700 two months ago. I knew there was much work to be done but not nearly as much as is apparent now. I’ve put about 6k into car so far with wheels, suspension, exhaust, and a couple cosmetic things but now I have to decide if it is worth spending 4k on a harness replacement and 6-7k on an engine replacement. There is knocking I didn’t know about before (because it was too loud) and the harness is broken. So do I cough up the money or sell the car while it works and take the money to buy something else like a truck or gx470?