1st of all, congrats on your new GS. You are right, it’s not fair to compare the 740iL to the GS. The 740iL should be compare to the LS series instead. Having said that, it seems like you drive your car pretty hard and the BMW is more suited for that kind of driving. The transmission in the Lexus is program for fuel economy, if you want more instead acceleration, try using the sport mode on the ECT or use the manual shifter. Laying down rubber may be nice for a boy racer, but it’s a Lexus after all. When your burn rubber, you are actually losing traction and it will slow down your acceleration. Just look at the numbers, the 740iL 0-60 in 6.8 sec. and the GS460 0-60 in 5.5 sec. More than 1 sec faster. That goes to show you, just because the GS doesn’t feel like its going fast, that doesn’t mean that it is not.
The BMW does handle better, but I think anyone who have done their research should have known that before going into the dealer. I am sure your passengers will appreciate not being thrown around in the GS like they were in your old BMW.
If you are going to compare the GS to a Chevy Cavalier, your opinion may be bias. Sounds like you like to drive your car hard and you miss your BMW.
The Nav while moving can be over ride, and the reliability on the Lexus should be better than the BMW.