No not really because there are other items aside from just the engine that make the STi an improved package over the WRX regular, and the cost difference between them is less than if you were to do these upgrades yourself.

Either way the 2010 and 2011 models are dog's ass ugly so it doesn't much matter to me. I also am not a big fan of the WRX or STi at all but I do recognize the difference in offerings.