In all honesty Yeew... I wouldn't waste my money... Even on a manual 6 speed the results would be negligable. That 10 to 12 HP would be probably possible on a brand new engine and that extra figure would be at the flywheel! Once it has travelled through the drivetrain it may be as little as 4 or 5 BHP extra at the wheels!
On a used Q-system the torque converter would eat up the extra horse or two left and say "thank you very much I'll have some more of that
" with no improvement whatsoever... Auto's aren't designed to transfer all the power thus the different performance figures between manual and auto's with the same 190 bhp at the flywheel.
The only viable route to true performance on a 2.5 V6 24v Q system is to junk the engine/ gearbox / ECU's / wiring loom and install a 3.0 V6 24v with a manual box complete with, linkages, gear selector, ECU and looms...
Then and only then would a remap show any benefit.... It's possible to rebore the 3.0 ltr up to 3.6 ltr for serious power results.
Save your money, bide your time and wait for a rear ended 166 super to come into your local salvage yard.... Buy it and RAPE IT for what it's worth
Otherwise, you are going to waste a hell of a lot of money on a "hamstrung" engine and power "crippling" gearbox with very, very little to show for it.