Hey mate, wasn't trying to have a go, but by the way it sort of came across like you actually didn't know to much and like so many people out there just gave a what do i do to get "a daily street car that does fast times".
I don't have a problem helping people out on what mods to do if they know what they want and want to inform me and other what they are trying to ask for in terms of engine, or drivetrain, or electronics or whatever.
There is so much stuff out there in this site it is rediculous, so thats why i said in my opinion go 30 bottom end, 3540 turbo, blah blah blah. You never actually said what you would like to do or budget. The only thing you said is that the car is auto. How is anyone going to give advice on little information.
Well you can work out the engine part, but being the auto thread, It depends what you want for power output. The biggest and easiest thing would be to get a shift kit. A simple stage 2 shift kit. This will help stiffer shifts and any flaring between gears and prolong box life and help it cope with any extra grunt. You need a bigger oil cooler, or well an external to the standard radiator cooled cooler.
Once those mods have been done and don't expect to pay more than $500 with everything fitted(if you can't do it for your self) the next place to go from there, get a higher stall converter. Try for about 2800 or there abouts, depending on turbo setup. That will let the engine to increase revs higher and get greater torque to the wheels, then it'd really start to cook. With 250-300rwkw and just that setup, expect 11's or at least low 12's and your box could/should handle it.
The rest is up to you.
Rob