by starting at the throttlebody trying to improve airflow on a stock motor,you're pretty much working backwards
larger TB will be choked by the stock intake..replace the intake and TB with larger/better flowing pieces,and they'll be choked by the stock heads..
to make any power,you need to start at the heads..replacing the intake manifiold alone will usually net about 10rwhp,more if you replace the heads as well
so as the others said,you wont notice anything but a lighter wallet for now
1987 Notchback - N/A stock 302, TFS heads, Holley Systemax, FTI cam, Astro A5
Best so far: 10.92 @ 123mph with a 1.49 60ft