The 2Pis are the smaller speakers compared to 10Pis, etc, so they'd be suited to the home environment and not large clubs etc. 4PI Pro's would be great for clubs. PA speakers themselves are really only different in that they can go real loud - but nothing else can be known just by the name. Its also nothing to do with "horns" which are not limited to PA use. Pro Sound woofers like Eminence shouldn't be looked upon as "bad" just because its got the word "PA" attached to it. The entire thing needs to be evaluated to see if its suitable for use in your HiFi application.

Those slimline towers with the 6" woofers work too. I think the 2 Pis use 8" ers. The 4Pis use 15"ers. Its not really the diameter of the driver thats the issue. Advantage to using large diameter woofers? Nothing, if its a piece of crap. But if its something good like JBL 2226, then its a different story. I have JBL 2225H 15" drivers that I use for the midbass/lower midrange. I use them because of their excellent directional control characteristics, low distortion, high efficiency, and high maximum output capabilities. Basically without knowing anything about the drivers themselves then we cannot make a decision. Driver diameter means just about nothing to me. The only thing I like about large diameter woofers is that people can go "WOW!" when they seem them :-)

Implementation of the parts also plays another huge role. Good quality parts won't sound good unless they are setup correctly. EG: Crossovers, boxes, baffle spacing, etc.

I think you'll be happy with the 2PIs though. I dont have 2 Pi's, but looking at the parts used and the design that Wayne has done for 'em looks like they will be great performers especially for the cost.

Adrian