Try 8.75No there's no performance upgrades to be made outside of hardware via weight reduction. The plaid record is something like 8.83 1/4 mile. Start with light weight forged wheels and carbon ceramic brakes (unspring weight). That's about all you can do beside starting to gut the interior like the record setting car.
-Improve efficiency (I know this is not easy... lot of trial error)
-Improve aero (last 3rd of the 1/4 maybe ?) Ill be honest I did not really work on aero, its probably worse now then stock