How much oil are we talkeing here?
I know a waek point in these cars (one of many) where the plastic shroud wears a hole in the front of the intercooler. If you had a large accumulation of oil in your intercooler, its possible it all leaked out of a hole created by the shroud. I've seen it before. Intercoolers can easily accululaue a quart of oil over 100k. Where exactly was the puddle in relation to the engine? if it was at the very front passenger side corner, that is your likely suspect. It could also be from the IC piping as well if there is a crack or if the lower hose popped off.
Good luck and let us know what the dealer finds.
BTW, if it is the intercooler, they will want to charge you about $300 or more for a new one + labor. There are 2 for sale right now on E-bay for less than half that.