This is all in regards to the happy time 2-stroke engines.
When I say needle bearing, it's the wrist pin bearing which connects the piston to the connecting rod. Some engines using a bushing bearing in place of the needle bearing. A high quality needle bearing is superior to a bushing when it comes to wear. But the cheap bushing can take higher engine speeds than the low quality needle bearing used in some engine. A needle bearing doesn't need as much oil as a bushing so that is why the needle bearing is seen a superior.
If the needle bearing holder were to fail, the engine would be basically destroyed. An easy way to destroy the needle bearing holder would be to over rev the engine going downhill.
It is difficult to tell what type of wrist pin bearing you have unless you take to cylinder off or you could ask the seller. As for switching bearing types, I've never done it and don't know how much it would cost.
Here is a picture of a wrist pin bushing:
http://motorbicycling.com/f30/bicycle-engine-total-tear-down-391.html#post3236