Pls help...6 cyl or 8 cylinder Luxury autos ?

Some things that affect fuel economy are driving conditions, i.e.., stop-and-go, driving on hills, highway, etc.; driving style; engine and transmission; payload; and vehicle weight.

In general, larger cars have larger engines to pull the weight of the larger car.

EPA fuel economy estimates may or may not reflect an individual driver's results due to the many variables, but they are good for comparing between different vehicles. Lexus offers only one engine choice for a particular series but Mercedes offers some vehicles with engine choices - for example, the E-class can be had with 6 or 8 cylinder engines. If most of the driving is in an urban environment and the driver has a gentle foot, the smaller engine will probably offer better fuel economy than a larger engine.

As far as the difference in cost, the EPA estimates will show relative differences in fuel cost.

Right, also don't assume 8-cyl or 6-cyl is the only determinant. Lexus

8 cylinder engines are very efficient and get better mileage than some other manufactures' 6 cylinder engines. Look at the gas mileage ratings for comparison purposes, not the size and configuration of the engine.

I think another thing to consider is gas requirements. The LS430 needs premium, so that will run the cost up too.

MY SC400 (8 cyl) gets better mileage than my SC300 (6 cyl)

Hi Anna, even with today's gas prices, your major concern when purchasing a vehicle is to look at the estimated annual depreciation of that vehicle. A Lexus will depreciate far less than a Mercedes or GM product. That said, remember, a powerful engine is an open invitation to speeding and jack rabbit starts, hence you should also factor the cost of police tickets when considering a V8 instead of a Six. My Lexus Six has already spares me a couple of speeding tickets annually!!!!!!!!!!!!!1

I don't know about that, my SC300 is almost as fast as my SC400 stock for stock in the 1/4 mile... and the SC300 is capable of reaching speeds just as high as those reached by the SC400 (both are limited electronically at close to 150 mph). I do not agree with your statement regarding excess speeding in an 8cyl. vs. 6 cyl. at all.

In fact, the IS350 (6 cylinder) is FASTER in the 1/4 mile than the GS430 (8cyl)

No offense NYLexsc, but I rarely watch my speedometer when driving with traffic, I just follow traffic unless some slow poke is driving under the limit. In that case I try to pass the slow vehicle, but my 6 cylinder does not encourage me to take chances, so many times when I have to pass up "Passing a slower vehicle", I found myself lucky when I see a parked police cruiser off the side of the road. Had I had a V8 and passed the slow poke, I would have definitely been ticketed, and that happened to me at least twice a year, ergo, my comment on staying with a 6 cylinder

I've also owned both, and my SC400 was also better than the SC300.

I've just traded in my '02 GS300 for an '04 GS430, and the 430 is getting about 2mpg less than the 300 got :)