power to price ratio is around the same as an sr making 305 horse, but you get the power all the time with the lsx motors, not just once the turbo spools up. There are lots of ways to make this build cheaper aswell, ie buying and iron block and boring it out and putting ls1 heads on it, little heavier but you will never have to worry about your block 
I was planning on doing an lsx swap and it would cost around the 6k mark to do it myself