Differences between '05 and '06 1.6 Engines?

Hi, I'm new to the Aveo forum, and I'm buying an '05 Aveo tomorrow that might need an engine:screwy: in the near future. (Hey, the price is right:sunglasse)

So, I looked for an engine on eBay, and the '06 ones cost about 1/2 of what the '05's cost.

What's the difference? Can I put an '06 engine in my '05 without too much trouble? This is a 5-speed, with no A/C, basically a bare bones car.

TIA, Ed