The only engine thats in a Lexus that can be considered slow is the 3.0 liter V6 found in the ES300 and the RX300. That'll be changed in 2004 when the ES330 and RX330 are due out, both with around 250hp, with an all new very refined 3.3 liter engine. The new RX330 looks fantastic too with a very BMW X5ish stance.
Actually, its a common misconception about the ES300, its only 20% a Camry. When you drive the two back to back (at least the new ones) they are totally different cars, the ES is a lot smoother and more refined, in fact, its almost as smooth and as refined as my LS400 which was nearly twice the price. Plus with the Lexus you get the brand prestige, the service and the longer warranty, plus variable valve timing in the engine which the Camry doesnt have. My son is looking at one of these, and I get them as loaners, its a really really nice car for what it is, but it is sluggish. The new engine is needed badly.
1995 Lexus LS400
Weight: 3650 lbs.
Base Engine Type: V8 / 4 liter
Horsepower: 260 hp
Torque: 270 ft-lbs.
Mine's a 98 with a weight around 3750, 290hp and 300ft-lbs. It'll do 0-60 in 6.3 seconds and do a 1/4 mile of around 14.6 right out of the box. I've seen LS400s like mine do sub 14 second 1/4s with very very little modification. I actually prefer the way my car drives to the way the LS430 does, the throttle on the LS430 is a little heavier, a little more german, and I think it makes the car feel sluggish, doesn't feel as quick as my 400 to me. Plus the 430 is limited at 135, where my 400 is limited at 149, and yes I have tested that
Its a fantastic car, I can't say enough about it. Probably will replace it with a new 430 when the time comes.