I had the use of an echo 1.5 for a few months a while ago - not a very inspiring drive.... the worst part was the gear ratios, they were diabolical!!

recommend driving one before attempting to put one in a brick

However, I bought an early Honda CRX in driveable condition for $350 - twin cam 1.6 with the internet full of mods, turbo kits, you name it

Have to agree with Simon - if it's going to be done, it has to remain fun.