With 20k to spend, I say get the forged internals and a turbo, or twins if you feel so inclined. Either way you'd get your goal. You may even do it with forged or billet internals NA. Since mod motors are OHC, they're easier and safer to rev higher. 10krpm isn't out of your budget, but you'd have to get 4 valve heads to get there.
Another mod that will make you faster would be to get a carbon fibre driveshaft with billet aluminium u-joints.
Get some light racing wheels, and tyres that aren't TOO wide. If you lighten the rotational mass, it's much more effective than removing dead weight.
Man actually, light racing wheels, carbon fibre driveshaft, and diff gears (4.10) might get you to the 12s.
Suspension would help too. All the unsprung mass (suspension components, wheels, tyres, brakes) you want as light as possible, to enhance accelerating, braking and suspension performance.
I'd probably do as much of the above as possible with 20 grand, starting with forged internals, 4v heads, cams, exhaust (AND K&N filter, and fab up an intake tube out of the engine bay, ceramic coated), injectors, tune, driveshaft, diff gears, wheels and tyres, and suspension.
Exhaust system would consist of free flowing cats, 4 into 1 headers, and a good catback.