Definitely keep the stock/current ride height--those are big rims and with the LoPro's, you've already sacrificed some of the infamous Lexus ride quality--why give up more? It won't go any faster... :-)
The Gucci thing is neat-- if you like it, keep it. If not, well--it's your ride. In the words of Digital Underground, dowhatchalike.
However, I do have a stronger opinion about debadging the car (or any car, for that matter). Did you ever notice that the cars with their badges removed are *always* the smaller engine models? For example, people take the badging off of MBZ S430's and S500's all the time--but you bet your !Removed! that if someone can afford the S55 or S600, they will retain the badges for SURE, know what I mean? People who take the badging off are not fooling anyone--people know they are driving the "slower" model (get over it--if I wanted to drag race at stop lights I would have bought a 'Vette, not a Lexus).
I drive a GS300, and I'm frankly pretty happy at the moment with the fact that my $45 at the gas pump goes a lot further than it does for a GS430. You did the smart thing--the GS300 is still the same CAR as the GS430--you'll just get fewer speeding tickets, spend less on gas AND insurance than you would with the V8. I got nothin' to hide--if I really cared that much, I would not have bought the GS300 in the first place. My $0.02: Keep 'em on.
Regards,
Matt
2005 White/Tan GS300