N7SMI, check out my blog at http://wd4elg.blogspot.com
. I worked 225 with wires and 100 watts. I went to a hex beam and 500 watts and then really started getting competitive. Part of that is due to the improving sunspots...the 225 was in the doldrums from 2004-2009. You CAN do this, it just takes patience, time, and skill. Multiple yagis and high power decrease the time needed, but there is always a skill factor involved. Believe me, I busted dozens and dozens of pileups with 100 watts and wires. I did it with patience and by following the tips of the DX experts. My advice is to read, listen on air, ask questions, listen on air, listen on air!
Also, improve your antennas before getting an amp. Read about low band DXing with ON4UN, the ARRL Antenna Book. Vertical wires like an inverted L or a half square for the higher bands will get more out than a low dipole (lower angle of radiation!)
Never give up, share your stories, and most of all have fun! DX IS!