gas prices are extremelly high... is everyone MB owner really using Primium? If not would it be OK not to? I know it's recommended...

I am still using premium but filling up my SLK320 from just below 1/4 to full cost me over $40 yesterday !!!

Might have to switch to the middle stuff or even *gasp* the regular soon.

I alternate between mid grade and premium every other fill up. Between the SLK and my TReg it get a little to expensive filling with Premium only every time. I have seen no noticeable difference in performance by alternating.

Filling up with lower octane fuel will cause your engine computer to retard the timing and give you lower fuel economy. How much the fuel economy drops depends on a lot of factors (engine load, elevation, air temperature, etc.), but you could probably expect something between 1mpg and 3mpg, which equates to something between 5% and 10% for the SLK230

Where I live, regular 87 is now $2.03/gal and premium 91 is $2.23/gal. That's a difference of 9%.

Even if you save some money by switching, It's not going to be significant. Maybe 2.00 per week if you drive alot.

You'd save a lot more money by figuring out how to drive just 20 miles per week less than you do now.

thank you so much for the reply.
I had a Mini cooper before, and it was the same deal.

By the way, I was one of the first people to get the MINI in Boston, and I got lots of compliments and heads turning

With my SLK is the same thing.... Maybe because there aren't a lot of them around here bc of the weather ...

the ladies go crazy about it... Really cool.

I go with midgrade for now - it's 89 octane, and the recommended minimum is 91 (premium is 93, so I figure 2 points above or below will not hurt that much). I tried regular but I got such awful fuel economy you would have thought I was driving a V-8 in need of a good tune-up. S I switched back to midgrade and fuel economy improved quite noticeably - after about a week of riding around, of course, to let the computer make the adjustments.

Brian_R170 is absolutely right. Why hurt yourself more in the long run by trying to cut corners, instead adjust your driving to reflect the changing times. Running your engine on regular will not blow it up, but it will in the long run negatively affect performance and engine longevity (spark plugs getting fouled, etc) and require tune-ups before they are actually due. It's a Benz, treat it nicely and it will love you back!

I still use 93 octane, it's gas, the burns it, I need the car, so I pay for it. It's like food, I need it so I buy it.

Wrio, as for SLKs in New England is pretty infrequent, so they get a lot of attention, especially when it's copper.

The computer will adjust to the lower octane rating. So the mid-range will some some money will minimal notice in performance (unless you've got a lot of hills or do a lot of racing). I also use a Chase Shell card which gives me a 5% discount on Shell gasoling (only - 2% discount on the others), which REALLY saves some bucks.
We just added an SLK to the family (it's my 18th or 19th Benz - starting to forget how many), that's why I'm in this forum (for the first time).