motor knocks - rebuild or new?

I got a 1.0 3-cylinder metro (2000) that just started knocking all of a sudden. Dealer says it's piston-slap, but I don't think that would come on suddenly. I'm assuming rod/main bearing is the problem. the car has 82000 miles and I don't want to lose it! I drive 100 miles a day, and I like the payment ($0). I wouldn't mind buying a short-block, but I'm having a hard time finding one (I have the worlds slowest dial-up). anybody know where I can find a remanufactured motor? Or maybe a re-build kit for my short-block? How much can these motors be overbored? I don't want to pay to have the cylinders sleeved!

---many thanks for your input

your bette off just buying a JDM used motor, they have less than 40k miles and usually are under $400. installed about 10 of them and have yet to have had a problem with one

Try running a tank of premium through it. It shouldn't have any knock that early in it's life. It could be pre-detonation. Do you have a "check engine" light on?

I sure will try the premium...
The check engine light did just come on, but it was right after I washed down the engine - not right after the knock started. (I thought if I was going to be working on the engine I would clean it off - dirt roads!) I figured since it chugged & missed after I soaked the engine, then ran normally 1 minute later after it dried out, I just set off the light. I guess I'll take it to AutoZone to read that trouble signal too. It just didn't sound like a spark-knock.

Thanks !