CliffJumper

My wife is considering a GLS (if she decides to get 3 rows... if not, she wants a Cayenne). We test drove a GLS450, and the power felt "adequate". The brakes also felt adequate, but noticeably less confidence inspiring than those of her current Audi Q5 (and far worse than the Cayenne or my E63).

We've been considering the GLS550, but I noticed something surprising in MotorTrend's SUV of the year stats. The difference between the GLS450 and 550 to not only 0-60, but also in the quarter mile is only 0.2 seconds! I can see more aggressive gearing in the GLS450 could make 0-60 times similar, but I was very surprised to see the quarter mile times so close as well. Is the 450 significantly underrated?

If the acceleration between the two are so similar, that may not be enough to push us to a 550. However, we also place brakes and suspension higher up the priority list than most big SUV buyers. Is there any upgrade to brakes and suspension in the 550? I know there is a difference in tires that definitely help the 550's braking, but that can be easily fixed on a 450.

Is there anything else that makes a 550 a "must-have" car? We tend to like more performance-oriented versions of any given car, but don't want to throw away money unnecessarily.

Thanks!

rominl

there is another thread talking about 450 vs 550 and someone also pointed out the motortrend article. i can only say i drove the gls450 and gls550 back to back, there's no comparison. the gls550 is a lot more powerful, much higher tq, and it's effortless at all speed. when i drove the 450, i felt like i had to press hard on the gas pedal to get to the speed i want. i am not saying the car can't go fast, i am saying it takes more effort. with the gls550 the car feels like a rocket.

you have a e63s, i am pretty sure you can feel the difference easily.

i can't say for sure if the brakes and suspensions are the same between 450 and 550, but imho with 550 you get a lot more features as standard (led headlights, different body trims, etc...).

knpnj

Among other things, a factor that made us cancel a GSL 550 order and opt for a GLS 450 was the emissions.
The Greenhouse Gas Emissions ratings scale on the 550 is straight double that of the 450 - displayed on the front in every car at the dealership. (In case you care) It's of course not the mileage/mpg between these models that matters as much as how much in emissions each contributes.
http://www.fueleconomy.gov/feg/Find....37368&id=37399

baobay

I find the 450 has ample power and braking.

Mike450

Overall performance of the 550 is a step above the 450. The tires, suspension, and brakes all contribute to the greater sporty performance, not just the hp. If you measure the performance by straight line acceleration alone, there isn't much difference between the two models, assuming you don't define your life by half second intervals.

Personally, the 550 just looks sportier. That said, referring to the 450 performance as "adequate" is a gross under statement as well. It'll still outperform 7 out of 10 suvs you'll come across at stop lights or highways.

Life has choices. Either GL is a great choice.

silvertige

Besides increased torque and HP, which is significant, the front brakes on the 550 are 25 mm larger and the front track is 4 inches wider, rear track is at 1 inch.


All point to increased performance... acceleration/braking as well as handling.

CliffJumper

Thanks, good details to know.

jbak31

Do you know why the 550's track is wider? is it just the wheels it comes with? can you put the 550 wheels on a 450 to make it wider?

350MH83

Technically you can. But the law states that the wheel arches must cover all the wheel. So you will need to get the wheel arche extensions that come with the 550. That also means you need to swap the front and rear bumpers. In Europe, you can get that kit on any GLS as an option. In the US this is only on the 550.

silvertige

Wheels on the 550 are a different offset. Putting the wheels on a 450 would look horrible due to the lack of fender flares/ 550 body kit.

jbak31

I've actually been thinking of doing the opposite and putting 450 wheels on a 550. Probably 20" or maybe even 19". I guess I'd need 2" adapters/spacers then so that they don't end up looking recessed.

Mike450

No it doesn't, the difference in offset is ~22mm, or less than an inch.

It's the wider track of the 550 that fills the wheel flares.

jerome8283

It's the front and rear fender flares that make it wider too. The GL450 does not have fender flares. The fender flares come with the AMG kit.

silvertige

That offset takes care of the rear... and contributes quite a bit to the fronts, you only need 2 inches on either side. The wheels are also wider than a 450's which are also where there's a difference in track width. Guaranteed it's coming from the wheels.

silvertige

We're talking about track width not body width, the fender flares are part of the body kit as 2 of us have already mentioned.

Mike450

I have 20" OZ Racing et43 winter wheels from a GL550 on my 450. My point was, you're not noticing a difference from the OEM 20" et64 450 wheel.

jbak31

I do wonder if there's a difference in handling with 4" extra track width that you would even notice.

Mike450

If you build a 450 with active damping and active curve, with the same tires, it would probably handle within 95% of the same option 550.

Mitch Alsup

I have a <rather new> 450 GLS (Sept).
I find the power adequate.
I find the brakes a bit wooden.
I find the transmission very busy--so busy in fact I mostly drive it using manual mode on the tranny. I bet Merc programmed it to downshift at any sense of urgency to cover up the (otherwise) perfectly adequate motor.

OVer 5K miles, I am averaging 20 MPG.

Axxlrod

Reading this makes me think you are the target buyer for the GLS63. It ticks all of your boxes.