I original owner of a '98 C43 with 50K miles as my daily driver. Looked at new vehicles with more HP and found them too expensive. Any recommendations or thoughts on getting an extra 30-40 HP out of this beast without major work ($2,000 or less)? Are there any aftermarket chips out there? I heard somewhere there is a restrictor plate on the throttle body that if removed allows more combustion air, anyone heard that? Also, need recommendations for reliable shop in west suburbs of Chicago as I am just out of warranty. Thanks

Keep in mind I'm not as experienced with Mercedes engines as several forumites are likely to be, but I know some basics.

Air meters are sometimes quite a restriction to a throttle body's flow rating, whereas a 65mm throttle body might flow an estimated 535cfm, the air meter may very well flow say, 350cfm and your stock air cleaner 450cfm, each providing increments of restriction to the throttle body's airflow capabilities.
Higher rating designs are available for either, although in some cases a custom fitment/design may be required.

Always remember to upsize your injector ratings when increasing intake flow rates to maintain tuning and gain the performance benefits.

I'm not clear as to whether your car *is* an AMG enhanced model or that's the basic result you're after. I should think they would've taken care of shopping trolley intake restrictions already, if the former.

Exhaust tuning is always and forever a big horsepower increase without sacrificing drivability. Use reputable aftermarket tubular (high flow) header designs tuned by people who've done it on that model before or use computer models to get a setup right for your car.
Computer models, flow benches and dynos are good to suss out your engine's intake/exhaust flow ratios. Here's where your usable horsepower increases and fine tuning come from. You can tune an exhaust setup, throttle body sizing, camshaft centrelines and overlaps or even custom grinding styles and of course the kind of finish to leave in the ports if you're going to do some headwork.

Custom chip mapping is the best way to go to get your spark curve and shift points right for your individual setup and preferred fuel selection. Aftermarket chips are available for generic "bolt on" engine setups and should work well for the kits they're designed for and specified fuel grade. I think it a good idea to double check the setup and engineering guidelines on a dyno afterwards, in that case.

To be brutally honest, a well put together and finely tuned near stock engine is going to perform better, and give better overall power curves and drivability than many bolt on kits, from "mild enhancement" ones to supercharging.

If you'll tolerate my bantering, the models I've been messing about with so far for engines like the M117 respond so well to minor tuning effects, the 560 literally jump from stock 300hp outputs to 350 projected without so much as a groan.
I mean, say you get a 340 Mopar. You put aluminium heads on it and fuel injection and you've still got OHV to worry about, but you're already into the serious horsepower stakes.
And the little specs I've read so far on these "newer generation" Merc engines sound like some real Le Mans style engineering influences. I'd love to get my hands on some stock ones to play with just to see what they'll do with little more than some focused attention in the fine tuning stakes.

Jap engineering influences have gone full blown Euro by the way, I'm sure you know.

Below is a quote of something speedybenz posted on club202.com enumerating his performance mods to his C43. I flew to the west coast to take a drive in his car [not for engine performance mods, but to decide if I wanted to buy his complete custom suspension setup, which I am]. It is noticably quicker then my own C43. And most eveything he did, he did by hand ... I don't think it cost all that much either.

In another post, he's also mentioned he removed the screen before the MAS wire, stating the screen reduces response, and the MAS will fail for other reasons much sooner then from the possibility of dust making it through the filter and causing it to fail.

I'd say his C43 is probably the quickest normally aspirated C43 -- minus anyone who's done a 5.5L engine conversion, or a Stage II or III rebuild to the 4.3L, not that I know of anyone who's done it -- and hands down the abolute best handling one.

Regards,
Steve

P.S. If you care to read about what I thought, read my write-up here I wrote right after returning from NoCal. (I'm 98c43amg on that board)

theres not much u can do or get for 2k. don't expect 30-50hp either. For started you can try evosport under drive pullies, K&N air filter, Exhaust, and loose as much weight off the car as possible.