I'm still a bit crazy looking into this SC issue and finally contacted my local Mercedes dealer to get a price quote on the SLK32 AMG Supercharger, Intercooler and accessories to transform my car from NA'd to SC'd. Complete cost for parts $4,550.00 plus tax, install not included.

But, with the change, I found out I will need to change the wiring harness and ECU because the SC has sensors that interact with the rest of the engine systems. And still the question of whether the stock engine and manual tranny can handle the boost and added HP and what other bugaboos will come up when I change the ECU.

Looking at a big job with at least 6.5k in parts. And a dead warranty. I think I'll wait another 29,000 miles when it expires. I have ordered the new Berg Werks differential with a final gear ratio of 3.69. a 13% change from stock. It should be in mid February.

 

Wow I really have to say you are a SPEED MANIAC. The gearing and now this! It's okay, I know the feeling, modding gets addicting. My last car, the Eclipse GST in my avatar pic, I spent a whole $2400 just for some stupid, totaly uncomfortable, MOMO race seats with sliding brackets and some 5 point harnesses. Its funny to think I could have saved my money, put down another 2100, and gotten a supercharger for the crossfire...

Why dont you just get one of the superchargers or turbos thats made for xfire and comes with a warranty? I think the Renntech and Startech ones have an actual warranty when installed for the Crossfire, instead of trying to modify something made for the Benz?

 

It's the same product, and unbelievably cheaper from the MB dealer than the tuners... Go figure. I'm going to call the DC dealer and price the same parts for the STR6 even though they are identical to the SLK32 AMG. Perhaps DC will be a bit cheaper than MB.

Will post my results

 

HDDP:
In refrence to your question of the poweer train handling the extra hp, here is an earlier post I made a little while back:
Well guys, I finally got an answer to my question. Can the Xfires clutch, transmission and rear end handle the supercharger hp boost? Putting out big bucks for a supercharger is one thing but what about the rest of the power train?
Just got an e-mail from Cory Umenoto, tech manager at Kleemans and he said that they have modified a number of SLK320s (same as Xfires) and the Xfire power train can handle 400 lbs./ft continuous torque. He said that they have had 0 failures. Pheww! You gotta like it! OK so who is going to be 1st to make a supercharged 6 speed?
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I also asked the MB dealership to price out the SC but haven't received an answer yet. If you are right, then the ECU and wiring harness pricing and instalation need to be factored in. They still seem cheaper than Kleemans $9,500 plus $1,300 instalation, however, we do not as yet know what the ECU, wiring harness and instalation would cost. Please let me know how it all works out. A new harness is a little scarey!
PS I would also like to know how the new gears work out! I know with my 6 speed that it comes out of 1st gear pretty quick already. I am curious weather it may be too low for our trans or not?
Thank You and Merry Xmas!

 

I don't doubt that the 6spd manual driveline can handle the added HP and torque from the SC. I'm sure MB is very conservative in their set-up and design to make sure the car lasts 100k miles + before any major parts break. Afterall, the SLK320 and SLK32 were built as sports cruisers for the everyday driver. Almost every aspect of the car from engine to suspension was built for conservative comfort driving, not SCCA road racing. I think I have alot of latitude to goose the thing up and make it a very tweaky sports car.

Just the minor suspension modifications I have already done to the car have shown me that the platform has the potential of being a very competitive DS or CS class racer.

The addition of the SC & IC from the SLK32 or SRT6 obviously is not something I want to tackle myself as a DIY project, I will defer the install to the MB techs here in LA that have already done the mods on other SLK's & CLK's. I'm guessing I will be into this thing somewhere around $8,000 with parts and labor by the time all is said and done.

As far as the differential gearing change, again, I am going to have Berg Werks do the swap-out and pay the extra $600 for the labor for a total of $3,100. I agree with you about the first gear becoming almost useless, but right now 6th gear is useless and almost 5th gear as well.

The new 3.69 ratio represents a 13% change, so since I routinely shift out of first at 22 mph with the current 3.27 ratio, I would assume I would shift at 18.75 +/- mph after the change. Not a terrible sacrifice. But, worse case scenario is that it makes 2nd gear "torkie" enough to start from instead of first gear, without feathering the clutch too much.

I'll keep you posted. The first item to be done is the diff, which won't arrive until mid-late FEB.

So much for my SRT6 that I've had on order since July... LOL

 

Looked online and found berg werks is out of business.
I am interested in a rear gear change. What options do i have?
I have no need to go 150 mph, but light to light faster would be nice.

I have a 2004 with auto.