Anyone notice that when goosing the throttle at say 45mph (in sport mode) results in a somewhat sluggish or uncertain downshift? Almost like a bogging, then a split second of uncertainty, then it hooks up in the lower gear and shoots ahead...

 

yes.
I thought sport would make it more responsive or so, but it seems sport just makes it seem 'heavy' especially on curves, roundabouts, etc.

 

I've been using the manual shift mode (GS430) some and when you downshift, as in slowing down for a light or a corner, it does seem to go into neutral before catching the lower gear. The hesitation makes the car jerky and discourages me doing that. My MB SLK32 is much snappier in downshifting, even when done casually. I agree the ECT-Power or Sport mode doesn't seem to help it either. Since this is all electronic, we should be on the outlook for an upgrade; maybe press Lexus.

I'm not looking for a racer, just a snappier downshift

 

I definitely feel that it's an issue that remapping the tranny computer would solve. Feels like a first model year issue to me.

HEY LEXUS, HOW ABOUT A DOWNLOAD?

 

I agree that it is sluggish... I put that on their customer survey on the car. For comparison though i recently drove an Acura in this mode and it was slugish all around, seem like it was thinking wether you are making the right choice then doing it.