what should I start with?

[65StangerCp]

if you can do the work yourself then port the cylinder heads and get some long tube headers.

The ported heads flow alsmost as much as $1000 aftermarket ones and the headers will make even more power then the porting.

get a pertonix ignition modual and coil while your at it.-5 minute install

All in all your out 250 bucks and you get more than gears can get you for about the same price as just the gears. your gas milage will be hurt with gears and is my suggestion I got another 2 miles to the gallon out of the car.