Lamborghini is rushing to unleash a monster lightweight, rear-drive rocket in late 2008 as a last hurrah for the Murciélago supercar.

Sources at Sant'Agata say the car, dubbed the SV, will have even more power than the 641-hp V12 Reventón and will be blindingly fast in a straight line. Sources say it will have at least 220 pounds stripped from the Murciélago LP640's 3663-pound body, with some suggesting the savings could be close to 300 pounds.

Losing the front differential and driveshafts will save some 90 pounds alone, and dietary lessons learned from the Gallardo Superleggera will provide the rest of the needed weight reduction.

The welded-tube steel chassis is a more difficult proposition than the aluminum-bodied Gallardo, though, because most of the larger car's body panels are already carbon fiber. Only its roof and door panels are aluminum.

Lamborghini sources note the SV program has followed the Superleggera program by dividing the focus into three areas: interior, exterior and mechanicals. The interior will become carbon-fiber central, including the inner door skins, the seat shells and the center tunnel. Leather-lined door panels will be replaced by carbon, with a pull strap for a door handle, saving five pounds per door. Lamborghini also will strip out the audio system, and if it follows Superleggera precedent, it will happily sell it back to you as an option.

The electronic system to raise and lower the spoiler will go. Lamborghini is almost certain to offer two carbon-fiber rear wings, one far wider and more outrageous than the other. All-new forged and machined alloy rims will save at least 13 pounds per corner.

E-gear will be standard, both because it saves weight and because Lamborghini is worried that life will be busy enough for SV drivers without having to negotiate the open gearshift gate.

Weight savings also will come by replacing aluminum parts with magnesium. Nonstressed components also will be lightened.

Insiders are talking about as much as 680 hp and 516 lb-ft of torque from what may be the final iteration of a 6.5-liter V12 that traces its roots to the pre-Miura era. Expect new, lighter exhaust internals to serve the dual missions of cutting weight and easing back pressure.

Traction-control software will be heavily modified to cope with power being pumped exclusively through the rear wheels. The Murciélago has no skid-control systems.

The SV will have the fastest shifting in a Lamborghini to date, with insiders suggesting shift times could drop from the current 0.4 second to 0.2.

Besides building the road cars, Lamborghini also could use the car for homologation for privateer teams already running in the FIA GT championship.

With less than three years left before the Murciélago is replaced, the SV is almost certain to be the final update of the supercar. There is no suggestion yet that Lamborghini has plans for a Gallardo SV.