well weight to power ratio may be a factor...now..but who knows within the next few years...they could develop parts the could enable people like me to upgrade the rs into a fully blown wrx maybe sti it may cost money and man hours but in the end result i'll be able to look at my car and say..I built that not a team of engineer geeks or robotic arms but lil ol me....and those who say it cant be done take a look at the fast and the furious our favorite movie of all time and the supra they rebuilt...probably not that exact same one but the concept is that any good engine can be built from scratch!!