Dont have online nor the game yet...maybe one day though...

Cool!!
I wonder why there's no lag ^^

I've had one race so far with lag. And it doesn't effect your performance, it just effects where you see the opponents. You may see them right there in front of you, but they may actually be elsewhere on the track. I've seen the 2nd place guy get hit and I passed for a 2nd place win, but lag made me see him get hit, when he actually has already passed the finish line. So I actually was 3rd. But one laggy match so far out of 30 races, not bad at all.

In short, no slowdown for you, other players just might not be where you think they are. But mostly lag free for me so far.

Gosh , even more reason to buy a Wii now...