The Alpine is similar to a roofless Le Mans Prototype. It will easily beat the Lexus... But of course it also depends about how power each one has... But I think the Alpine will be very fast..
Well, at least we know hoe much power the Alpine has:-
TECHNICAL DATA
CHASSIS
Type: carbon monocoque
Suspension: double wishbones, pushrods, adjustable spring/damper assemblies
ENGINE
Position: mid-rear
Type: V8
Cubic capacity: 4,494cc
Maximum power: 450hp at 6,500rpm
Maximum torque: 580Nm at 2,000rpm
Maximum engine speed: 7,500rpm
Top speed: 320kph
TRANSMISSION
Seven-speed sequential gearbox
Rear-wheel drive
BRAKES
Front: 390mm x 32mm vented discs with six-pot callipers
Rear: 355mm x 32mm vented discs with four-pot callipers
WEIGHT AND CAPACITIES
Weight: 900kg
Weight distribution: 47 / 53
Fuel tank: 75 litres
If we assume the Lexus is similar to a GT3 or GT500 car, we can make a guess as to which will be faster.