From Jayski.com:

Brewco Faces Dilemma with Waltrip: UPDATE: Brewco Motorsports will have to decide what to do about the Busch Series races in which Yard-Man is a sponsor, the next of which is May 5 in Richmond. Michael Waltrip was supposed to run those events, but his Nextel Cup sponsorship from NAPA conflicts with Brewco's associated sponsorship from Federated Auto Parts. In an attempt to appease everyone, Waltrip ran the Yard-Man paint scheme with the #99, which represents the Busch team Waltrip owns. But a Brewco Motorsports crew worked on the car during the race and it was a Brewco car. Meanwhile a Michael Waltrip Racing car had the #66 on it with David Reutimann as driver. NASCAR did not award Brewco the points its team earned through Waltrip, so the Brewco team is now in a quandary for the six other races scheduled this season. That was a 73-point difference and six spots in the points standings.(NASCAR Scene)(4-27-2006)
UPDATE: A sponsor conflict will preclude Michael Waltrip from driving for Brewco Motorsports in any more Busch Series races this season, team owner Clarence Brewer confirmed Saturday. Waltrip's spot in the #66 Ford will be taken by Scott Wimmer, who already was splitting time with Waltrip and Ken Schrader in Brewco's second car. Wimmer will drive the #66 next week at Richmond, replacing Waltrip. (NASCAR Scene)(4-27-2006)