I would go with the Tanabe NF. nice ride and drop

 

I have the F-Sport Springs and Swaybarss, front and rear installed on my 2008 GS350. The most noticeable improvement was the sway is GONE but the ride is HARSHER. Almost as harsh as my 2008 BMW 5 Series with sport package but "almost" because the BMW has noisy Dunlop run flats and the Lexus has the Yoko Advans A10, a summer tire (but awfully noisy and harsh from day one).
So, the dilema IMHO is lowering the car will almost always mean harsher ride. I'm not a rocket scientist but remember reading that it has something to do with shorter spring height increasing the amplitude and spring rate to "control" the motion of the car BUT loosing the long rebound action of stock springs that is almost always associated with a soft, cushy ride.
I'm soon replacing my Yoko Advans with the Michelins to see if it gets a little softer...if not, I'll put back my stock springs.
Funny...I think a Lexus should be cushy with sway control but I accept the harshness in my BMW because with that car, its the whole package I guess.
Advice: Before you spend the dollars, try to cop a ride with someone who has changed their springs.

 

I've got Tanabe NF. The springs after settling ended up dropping the car at least 1/2" lower than advertised. The drop looks great but I definitely had to do some fender work to help with the rubbing issues. I've got 20s and the fronts rubbed like hell. Had to roll the front fenders. The rear fenders I ended up cutting (hated to do it, and my wife still doesn't know....shhhh, it's her car, too).
One person mentioned the height being uneven from the factory. I've noticed that as well. The driver side on my car is about 1/4" lower than the passenger side.
As for ride quality, if you get bigger wheels with thinner rubber you'll definitely feel the road a lot more. It's been over a year and a half and my wife still complains about the ride. To me it's fine...=)