in the beginning the engine was considered to be "crappy" especially compared to the K20A2 from the RSX-S.
but there are many people that have put down respectable power with the K20A3, and its really not as bad as many people make it out to be (mainly people who don't bother to learn more about the engine). it has a decent amount of torque for a civic which is a trade off since it doesnt have that much top end power.
I/H/E/KPro would put down great power. brian crower and skunk2 also make camshafts which when combined with a PRC intake manifold and you're getting extremely good power out of your "dreadful" engine. of course thats only if you plan on going all motor.
boosting would be a different story, as many EP3 owners have put down as much as 300whp with a turbo kit (rehard and cybernation).
best bang for the buck? kpro definitely.
dont be deterred by the ignorant remarks about the K20A3, there is hope.