Gas mileage wise, SC is still better than LS if the same six speed though.

 

None of my cars get what would be considered really good gas mileage. Like Jabberwock, I don't drive significant miles on my vehicles. none of the cars I own are daily drivers. I'm with you on driving with the top down. If I can't have the top down I'll drive a different vehicle. Only the company car is driven daily. So I'm in that gas mileage doesn't really matter to much to me.

 

I am pretty sure all model years of the LS430 have had higher (better) MPG ratings than the SC430 regardless of transmission.

 

According to published data SC is slightly better than LS in MPG, for example 2006 year models; It matches my experience as well.
https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=22070&id=21679

 

The link may not work, so here is the screen cap.

 

Correct me if I'm wrong, but the 6-speed in 06+ is only when you're in S mode. In auto mode, you're cruising in 4th gear, therefore , if you want to have a high mpg, you must drive in S-mode.

 

Is that the same case with 02-05 models? Only cruising at fourth gear in auto mode?

 

Pre-06 SC has 4-speed transmission, so yes.

 

Not true. I can count the shifts in Drive. Goes all the way to six. I have to hold up my other hand. Oops gotta get my hands back on the wheel. And the 02-05 had a 5 speed transmission not 4.

 

How much does the LS430 weigh?

 

06 LS430, curb weight 3990 lbs.
04 SC430, curb weight 3840 lbs.