I would assume you are talking about the speakers, not the subs. The perfect series only comes in component speakers with a 6.5" woofer. A component system is a woofer, tweeter, and passive crossover; all of which are separate pieces. The Kappa's come in 2-way, 3-way, and component systems. Infinity's speakers are not really known for their mid-bass, so your friend is kinda wrong there. Good midrange and highs though. The Perfects are expensive, much more so than the Kappa component set, and way more than a set of 2- or 3-way Kappa's. With the 2- and 3-way systems you don't have to worry about mounting the crossover and tweeter, or wiring them all together. But the component system will sound much better due to an independent woofer and independent tweeter.
Hope that helped a little,
Steve