For the 2004 season, four teams got their hands on half a dozen R-GT's. From Europe, the highly-rated Dams outfit run by Jean-Paul Driot would be contesting the FIA GT Championship whilst in the State's, Krohn Barbour's new team planned a two-car assault on the American Le Mans Series. Out in the Far East, the Japanese Lamborghini Owners Club and Amprex Motorsports squad would both enter R-GT's in the Japanese GT Championship. After a winter of intensive development though, Reiter Engineering (who had originally engineered the R-GT on Lamborghini's behalf) wanted to do the first competitive run.

The location was Valencia, Spain, in mid April where Pete Kox and Oliver Gavin would contest Round 2 of the FIA GT Championship. Things started very promisingly with a fifth place spot on the grid being turned into a lead of around 30 seconds by the first pit stop. However, the team lost ground after Gavin dislodged a fuse while getting in. Rejoining fifth, the Murcielago eventually recovered to take third, just 61 seconds behind the winning Prodrive Ferrari after three hours of racing. A couple of weeks later, Amprex Motorsport and the Japanese Lamborghini Owners Club took delivery of their Murcielago's, both cars making their JGTC debut in Round 3 at the Sepang circuit in Malaysia. Compared to the works-backed cars from Toyota, Nissan and Honda, the Lamborghini's were off the pace and out of their depth, neither R-GT managing to qualify in the 15 places reserved for 500 class cars and thus being relegated to the back of the grid behind all the slower 300 category entries. This became a pattern for most of the season and a 12th place finish for Amprex at Sepang wouldn't be bettered all year. In the US, Krohn Barbour received their pair of silver Murcielago's in time for Round 2 of the American Le Mans Series at Mid Ohio. Proceedings got off to a bad start when the Krohn / Maxwell number 6 car sustained heavy damage in a collision with a Porsche 911 during Friday testing. Unable to start, attention fell to the number 5 R-GT, Brabham and Kox battling for a top-three class finish all the way to the line but eventually being beaten to the final podium position by just six thenths of a second. By the time Round 3 came around just a week later at Lime Rock, the Krohn / Maxwell car was still being rebuilt around a new chassis back in Italy which meant just one car for Kox and Brabham.

One week later, the ALMS circus was at Portland for Round 5 and after two hours of racing, Kox was hanging on to the third-in-class Saleen when he was hit by a Porsche. Enough damage was done to the rear suspension to force them out of the race, the Krohn / Jonsson number 6 car also catching the ailing Saleen when halted by gearbox failure after two-and-a-half hours. Due to the delivery of faulty parts from the official supplier to Lamborghini, both R-GT's were withdrawn from Round 6 at Mosport after experiencing rear suspension problems in practice, the increasingly dispondent KBM outfit subsequently deciding to skip Round 7. They were back for the ALMS finale, the Petit Le Mans at Road Atlanta, but it was to be their last race with the underperforming Lamborghini's that were by this stage suffering from a chronic lack of manufacturer support. Car 5 paced itself and was well-established in third place when it span out on oil. After being dragged from the gravel trap, its engine refused to start. Car 6 meanwhile lost ten laps after also spinning into a gravel trap followed by 20 laps having an oil cooler replaced, but it eventually went the distance winding up 21st overall for fifth in class. In Europe, the Dams squad finally made their FIA GT Championship debut at Round 8, Imola. Despite the fairly lethargic pace set by the Far Eastern and American teams running R-GT's, there would still have been some optimism after Reiter's strong showing in Round 2 earlier in the year when an outright victory had been on the cards. Painted in spectacular orange and black liveries, Dams only received their cars in the fortnight building up to the race and with minimal testing, had a steep learning curve to climb.