Hey guys, can someone tell me about the different models for the 105 cranksets. I have this 1990 Sirrus and the crank looks bad. I was on Ebay looking at the 105's and there is quite a few different 105's, the one on the bike is 105sc.

The question is...would any of the 105's fit my bike without issues?

If I was to buy from someone on Ebay, is the seller's rating the only think to look at?
Please excuse my ignorance, I am probably only 1 or 2 people on earth who hasn't purchased on Ebay before.

Thx guys