TBS worked better in the old carbureted and early fuel injected engines where it would help with air mixture and help atomize the air coming in. on these newer fuel injected engines the fuel injectors do such a good job of mixing air/fuel that TBS does not offer any measurable benefit and would likely cause it to run worse as they system tries to adjust for it when nothing else has changed (think viper throttle body swaps)
If you were to do a complete intake to exhaust change then you would get some improvement but IMO not worth the cost especially on the 3.8.
As mentioned, a flash device and re-gear will be your best bet.
you didn't lose any power you just changed how it's distributed :thumb: