Bakusou Kyoudai Let’s & Go! Return Racers!!

The manga is set decades after the original series ended, focusing on the Seiba brothers who are now in their 30's, and a boy named Tsubasa who is taken care of by Go, the younger of the Seiba brothers.

In addition to the story arc sets in present, there's flashback stories that takes place during the original series. (http://mini-4wd.wikia.com/wiki/Bakusou_Kyoudai_Let%27s_%26_Go!_Return_Racers!)