DF03 is the name of the chassis used on the 'Dark Impact' and 'Keen Hawk' as well as maybe some others. It's one of Tamiyas newer 4WD off road buggy designs. It's like a modern day Hotshot design you could say - not meant to be a full racer.
Because there are lots of cars based on the same chassis - the wheels aren't referred to as 'dark impact' etc - but by the chassis name 'DF03'.
There are probably hundreds of designs of wheels that will fit but DF03 (available in black or white) will be a good choice and that's what I'll be using.
http://cgi.ebay.co.uk/Tamiya-53881-Large-Dish-Wheels-4WD-REAR-62-35-DF03_W0QQitemZ380083552292QQcmdZViewItemQQptZUK_To ysGames_RadioControlled_JN?hash=item380083552292&_ trksid=p3286.c0.m14&_trkparms=72%3A1301|66%3A2|65% 3A12|39%3A1|240%3A1318
here's what the rear DF03 wheels look like ^^