In stock form, the k20a2 from a 2002-2004 rsx type S has 20HP less than the k20a JDM.
The JDM k20a has higher compression, different cams, pistons, intake maniflod, throttle body etc.. It also comes with LSD and a better final gear.
Both motors make sense to me.
The k20a comes with LSD and good power potential with k pro and a nice exhaust/intake/header
The k20a2 with the right parts will make more power and you can also add the LSD for $850 etc..
Some people get the k20a2 and try to make it into a R but at this point it looks like aftermarket cams and other head internals will give better results.