03 Lancer ES. How do u get power?

First of all i dont own a lancer, its my friend's ;D. He asked me questions on how to make his car first. As of now, he has an AEM CAI and Greddy Catback. I know there is a very limited amount of engine swap you could choose from because of the money matters. If so, what more powerful engine than the 4g94 could be bolted on this lancer (not talking about 4g63t that will cost 10K to bolt on or evo engines)? Or we look into the other plan, turbo kits. I told him turbo kits aren't going to be cheap if ur really want power. Who makes the best turbo kits for this type or car.

thanks for your time.