Max engine output of the GS430 and LS430 engines may be the same on the test stand, but it's how much accelerator you need to apply to achieve that output. I had a '06 GS300 loaner car for 4 days, and I can tell you that it had a lot more initial pickup from a dead stop than my LS given similar pressure on the gas pedal.

IMHO, the LS's gas pedal is really de-tuned starting from a dead stop, so if you apply some gas, the car accelerates slowly. It's only when you really stomp on the gas that the LS takes off. On the GS, you don't have to apply as much pedal pressure to get the car to take off. I believe the throttle position sensor is going to feed into the ECU, and that will make to an air-fuel mixture. The other possibility is it's just the throttle position sensors that are different on the GS and LS. Either way, I don't see why one can't get the LS to accelerate from a dead stop like the GS given it does have the same engine.

 

That could be a MINOR factor given the more luxury focus of the LS but IMO not nearly as much as the car's weight and gearing. In the example you gave the LS gearing is 3.769:1 at around 4,000 lbs and GS300 with 3.91:1 and about 3600 lbs. Despite the lower HP it'll be faster at initial takeoff but very quickly drop back.

If you want the placebo effect of a faster pedal response time, might want to look into the Sprint booster. Not sure if it'll work for a LS430 but since they're a forum sponsor doesn't hurt to ask.

https://www.clublexus.com/forums/per...t-booster.html

It won't make your car any faster or make more HP, just decrease the pedal push required.

Edit looks like from their catalog that they do have an application for the LS430 2004-2006
http://www.jrponline.com/downloads/c...intbooster.pdf

 

When I had to replaced my O2 sensor's my ls430 ren so freaking fast that nobody could touch that thing no even close but doing so in acceleration the smell of sulfer do to fuel / air ratio intake was unbearable to the point didnt want to drive it over cruise control. But damn that thing was fast I mean it's very fast now still after all sensor's were changed and time to adjust but it surly was twice as fast before the change.

 

 

Put it in Power mode. That fixes the shift points and disables the smoothing in the throttle response.
If yer in Normal mode then it's configured for smooooth wafty limo stylee.
Power mode is for BANZAI stylee. :-D

Some vehicles can make gains from plug in chips, but not the LS.
My Kawasaki Concours 14 can be fitted with a chip that makes the bike think it's in 6th gear all the time.
What that does is disable the torque limiting in 1st to 3rd gears giving faster launches.
Yer not gaining any power, but disabling power limitations.

What ya can also do on the Concours 14 is get the ECU flashed.
That disables the torque limiting, gains 10-15bhp at the top end, gives 1-2Mpg better gas mileage and MUCH smoother throttle response.