Argue over PM keyboard warriors. Let the guys thread stay clean of unnecessary banter.
As said, a shift kit won't make more power. Firmer shifts will result and may give an impression of more go. No matter what you do to the gearbox, you won't gain more engine power. You will however change the amount of power lost from the engine to the rear wheels by going manual.
There are many options available if you want to feel like you have more power eg lower diff ratio.
How much more power are you wanting. You have a V6 and you can do little mods like CAI and extractors/exhausts and tunes, but in my opinion, save up for a stock V8 and save money by not modding your current ride. Because the stock V8 will have more power than a slightly modded V6 generally.
I have a $5000 shift kitted full manual auto in my 500hp VL Turbo. I have a standard 5sp Auto in my VZ Alloytec190 Calais. Now regardless of the power difference, the difference in a shift kitted auto is so different. Even under part throttle it does feel like the car has more go due to the next gear not sliding in like the gearbox in the Calais.
And the benefit of a shift kit is normally a faster firmer change hence, when you hit the next gear, it should change faster and more instant than a factory auto.
But in essence, a shift kit will only give the impression of more poke from your car. Engine power won't change and I wouldn't bother doing it unless you had mods already that have given quite a considerable power upgrade from standard.
Regards
Matt