http://www.edmunds.com/insideline/do/News/articleId=156467
GEILENKIRCHEN, Germany — Manhart Racing didn't think the 343 horsepower offered on the Euro-spec 2009 BMW Z4 roadster was enough, so it dropped the 5.0-liter V10 from the M5 sedan into the two-seat roadster. The results, needless to say, are spectacular, if just a bit excessive. The Manhart Z4 develops 542 hp, which is 42 horses more than the stock M5. That power gain can be attributed to its AC Schnitzer exhaust, HJS racing cats and a reconfigured ECU. The six-speed manual gearbox and differential from the E60 M5 are used, but Fichtel & Sachs provided a new clutch. Manhart claims the modified roadster makes it to 60 mph in 3.9 seconds and tops out at 208 mph. With a curb weight of 3,212 pounds, its power-to-weight ratio comes in at 5.93 pounds per horsepower — better that the Ferrari F430's 6.5 pounds-per-hp figure. Suspension changes include the addition of Bilstein B16 PSS10 coil-overs. Nineteen-inch blacked-out BBS Challenge rims wrapped in 235/35ZR front and 285/30ZR rear tires also improve handling. The 2009 Z4 Roadster with the Manhart V10 treatment costs the equivalent of just over $137,000. Inside Line says: Although impressive, dropping a V10 in the Z4 is kind of over the top. There are plenty of other ways to make that power without an engine transplant. — Mike Lysaght, Correspondent
