There seems to be a wide disparity between the genuine tuners, such as Kleeman, Renntech, Brabus, etc., and the "power chip" marketers.

I don't see any point "ECU tuning" a V6 engine since the ECU gives only at most 10 hp/10 torques for $1,000 to $1,200. Bottom line is that the V6 engine will still be pretty weak compared to a V8, and horribly weak compared to an AMG, and when all is said and done, I think ditching the V6 and buying the same model in AMG may save a ton of money.

And then there are the $49/$69/$99 firms that see some sort of "performance chip" that requires splicing into the IAT senor with a couple of Radio Shack resistors, and thus giving "50 hp increase." I know better than toy with the Mass Air Flow sensors. Guaranteed error codes.

And then there's the kind that plugs some sort of mystery box into the ODBII port for $150/$199/$249. Hoping that the ECU can read and get familiarized with the new settings.

I'm kind of lost here. Is this whole thing a waste of time?

 

I can't say that the "whole" thing is a waste of time, or a sham, but I have not found any credible (non-marketing) source who can testify to or verify any meaningful gains from the performance chips or "mystery boxes". IMO it probably depends on what you're starting with and I do not believe the MB, BMW, Porche, or Audi, etc. engineers are leaving much on the table in the tuning of their engines that can be so easily extracted. There is a reason those "genuine tuners" can command the fees that they publish.....

 

There are a few good things about these tunes. First, most of them remove the speed limiter. Second, they generally provide a better throttle response. That's not necessarily an increase in HP or torque, but just a "remapping" on the interpretation of the accelerator pedal so that some of the typical MBZ hesitation is eliminated. Finally, if you want to install headers and high-flow cats, this type of tune can be very beneficial to eliminate errors when removing the secondary O2 sensors and doing some mapping for the improved exhaust flow.

But, I do agree - if you want big power increases, trade-up from a V6 to a V8 or to an AMG. In the long run, that will be the best money spent.

 

I think the tunes from oetuning, kleemann and eurocharged are worth it in some situations. Of course the more you start with the more you get. You are going to get much better gains from having a tune done on a V8 than a V6 and way more if you have a supercharged or turbocharged engine. I did it on my C32 and I was very happy with it. $300 or so when on sale isn't exactly the difference between trading up to the equivalent amg. If you are wanting a mild increase it is a good idea, if you want heaps of power then get another car.

The other things you mention are a complete waste of time and should be avoided.

 

In a normally aspirated engine, I have yet to see before and after dynamometer results from a $300 showing anything more than a 3% increase in HP or torque. Honestly, I think you'd get better performance by removing some weight - CD changer, spare tire, tools, and stick to smaller, lighter alloy rims instead of big "show" rims.

But, as I said, it's not a waste of money if you want to remove the top speed limiter and get some better throttle response. Or if you intend to do some exhaust work or add on a forced-air induction system (i.e. supercharger or turbocharger).

On supercharged and turbocharged engines, there is a huge difference possible as the tuning can increase boost over what the put into its programming. The manufacturers generally build their engines to withstand more boost than what they allow, mainly to increase reliability. I won't say that overboosting will hurt anything, but it could shorten the life over time.

My comment about it being trade-up is that you aren't going to take a CLK320 and get a $300 tune to make it perform as well as a CLK500. The same goes for a CLK550 - you won't get to CLK63AMG sspecs on it with a $300 tune. If you have a V6 and want V8 power, it can be done, but it will costs many thousands of dollars in work. Something like a Kleeman supercharger will run over $12K. For the price of a V6 + $12K, you could trade to a CLK55 of the same year, maybe a year or two newer. Just to give you an example, I put my car (MY 2007 CLK550 Cabriolet) into KBB and it gave me a "private party" value of about $22K. The same thing in the CLK63MG is $27K. So, theoretically, for about $5K, I could trade up to an AMG, giving me a nearly 100HP boost in output and shaving 0.7 seconds off the 0-60 time. Honestly, I don't think I could make my CLK550 do that for twice the price.

And let's say you have a MY2005 CLK320 Cabriolet. KBB lists it at about $12K. So to go from it to my CLK550, for $10K, you increase over 170HP, and shave 2.6 seconds off the 0-60. Again, you can't even buy the parts for a Kleeman SC for that, and then you won't see a 170hp gain.

Of course if your objective is to have fun with your car and do the work yourself, tweaking and tinkering, then it would be more rewarding to spend the money on these aftermarket upgrades. Just don't expect much from a $300 tune. It's probably worth about $300.

 

Bear in mind my $300 example was my supercharged c32 with a lot of bolt on mods. There were good gains. I agree that it is a waste of time for the 320 & 500.