What Diff For Bike Engined Car

[Johnnybizzle]

Hi,

Currently building cbr 1000 engined roadster, i have been told 3.14 or 3.16 would be best bt theyre rare and expensive, would a more common diff like 7" 3.92 diff work or would i be limited top speed or poor accelaration,

Any advise appreciated, Higher ratio the better?

Regards Jon