As the saying go there is no replacement for displacement. For a serious and reliable package I would pass on the LSx/LQx based engine and go for at least a 620 hp 572 crate engine or if you don't mind buying nothing but the best fuel go with the 720 hp GM 572 or one from any of the larger builders. Once you have to start adding the boost you start to kill the reliability of the engine. If you consider a base engine, a forged bottom end, turbo assembly, a built transmission and all the parts that will be required to install the engine you will probably be at about $15,000 especially if you have to pay someone to do all the work.