Cheapest is trading it in.
Next cheapest is to swap out the entire engine from a crashed WRX- that is actually not bad; nearly everything is a direct bolt up. You can sell off the original engine to recoup costs. You will be able to find specialists who have done this.
You can add a supercharger, cardoc has a thread on this board detailing his project on this path. Not remotely for the faint of heart.
Next cheapest is to swap out the entire engine from a crashed WRX- that is actually not bad; nearly everything is a direct bolt up. You can sell off the original engine to recoup costs. You will be able to find specialists who have done this.
You can add a supercharger, cardoc has a thread on this board detailing his project on this path. Not remotely for the faint of heart.
