guitar amp

One of my hobbies is building cigar box guitars. They are simple instruments and fun to build. Building these is what got me back into electronics. I built an amp based on the lm386 and it actually worked better than I was hoping for, now I would like to build something with a bit more power. My search came up with this http://www.learningelectronics.net/circuits/guitar-amplifier.html Not a power house but fits what I want, I have two 8 ohm, 8" Fender speakers that I bought for this build. According to the circuit description I should be able to get 18 Watts from it by wiring the speakers in parallel. Once I get the project started I can start a thread in the "project logs" if any one is interested.... Any input is appreciated. I will be using both electric and piezo pick ups.