The exchange on the radio between frustrated Kurt Busch and car owner Roger Penske was far from cordial. While neither resorted to yelling, their back-and-forth made it clear neither was too pleased with the other at that moment. But that was last week, during another long day on a short track.

MIAMI—Less than 24 hours after he won a Sprint Cup race at Martinsville, NASCAR champion Jimmie Johnson was in Miami to be the leadoff defense witness today in the Helio Castroneves tax-evasion trial Johnson testified that a lawyer who is also charged in the case has a sterling reputation in the motorsports world. Johnson, the three-time defending champion of the Sprint Cup Series, said Michigan lawyer Alan Miller has many clients in NASCAR and the Indy Racing League, a circuit where the Brazilian-born Castroneves is a top driver. Both Castroneves and Johnson have received financial guidance from Miller.

MIAMI—It would be terrible for Penske Racing and the sport if Helio Castroneves, the popular Indy racer and “Dancing with the Stars” champion, were convicted of tax evasion, a top Penske official testified yesterday.

MIAMI—Race car driver and TV dance celebrity Helio Castroneves never sought to break the law in his financial affairs but could have avoided all U.S. tax on about $5 million if he had relocated from south Florida to Monaco as envisioned, an accountant testified today at Castroneves’ tax evasion trial. Kevin Savoree, now an executive at Andretti Green Racing, said when he handled accounting work for Castroneves in 1999 and 2000, the plan was to set up a legitimate deal in which much of the two-time Indianapolis 500 winner’s income would be deferred. That meant his taxes owed to the IRS also would be deferred until he actually got the money.

MIAMI—Race car driver and “Dancing with the Stars” winner Helio Castroneves never sought to evade U.S. income taxes and planned to pay the Internal Revenue Service when he received $5 million from a deal made a decade ago, his attorney told a federal jury Tuesday. Defense attorney Roy Black said in an opening statement that the Brazilian driver, a two-time winner of the Indianapolis 500, knows nothing about U.S. tax laws and relied on experts to handle his finances. Black said there was no scheme to hide money from the IRS.

INDIANAPOLIS—Helio Castroneves is being replaced on Team Penske by Australian driver Will Power—at least until the two-time Indianapolis 500 winner’s tax evasion trail is resolved. Castroneves, who has pleaded innocent to charges of conspiracy and tax evasion involving about $5.5 million in income stashed in offshore accounts, is scheduled to go to trial in Miami on March 2, just over a month before the IndyCar season begins.