Hey, no offense or anything. The ES was not tuned or made to be a sports car. It was designed as a luxury cruiser. I think the same will go for all lexus cars. Even mine.
Keeping that in mind, I'm not saying its impossible to make it quicker/handle better. My car is now a far cry from what it used to be when I first got it. It's just going to take a lot more work, determination, and money....did I say money....to make the car quick and handle great. It's not a simple honda or something where the aftermarket parts are cheap and readily available. Most work on lexus cars is often times custom/one-off...this also means quite costly. Take for instance a turbo kit for my car costs about 5-6K and will net me about 300-350rwhp. While on a honda a $3k turbo kit can get it to around 275-300rwhp. Anything is possible, its just how badly you want it.
I've never looked into the ES line, but I'm sure some company has made a custom supercharger setup for it. Obviously it will cost more than the 1MZ TRD supercharger, but as I said...a Lexus is more expensive to mod.
Good luck!
__________________
05' Lexus GS300 Crystal White
Electrical & Lighting: Custom M5 Bi-Xenon HID Retrofit (Done by me), HID Foglights 6000K, Optima Yellow Top
Suspension & Brakes: Tein Flex Coilovers, SupraTT 4pot Calipers, G-Stop SS Lines
Engine: L-Tuned Exhausts, SRT Intake
Boost in the summer 2JZ Power!