aftermarket exhaust

The only aftermarket one I've seen/heard in person is the Eisenmann one on Vic55's car. Sounded mean but he also has the secondary cats and perhaps primary cats removed. Someone that knows for sure will probably chime in.

You named all the major players. Understand up front that you will get ZERO power gains from any of them. In short, you lose as much grunt as you gain in sound.

To avoid that, I am actually playing with modifying the OEM exhaust.

The need for new headers is a nobrainer. You need to decide if you want shorties or longer ones. Shortys have the advantage of bolting right up and remaining emission legal. Long ones can add about 10hp over the shortys. I choose shortys.

There are primary and secondary cats that you may or may not choose to cut out.

Next is the resonator. I removed mine and love it. However, others have had good results from keeping the resonator and removing the secondary cats. In any case, you will always need to balance the system (backpressure is critical).

Last is the mufflers. You can either replace the OEM ones and add tips, or take the oem ones and have them gutted, which is what I am doing. Many tuning shops are going down this path.

My off the cuff remarks on the brands:
Eis Race (cat back). I think it is simply too much money for the quality and no gains. I'll take punched out AMG mufflers anyday.
Supersprint. WAAAY too pricey, even if it does include a header. Again, I am not interested in removing the cats. Retail is about $12k, but it can be had cheaper.
EVO is doing their own custom work on the OEM unit, and I'm not sure of the rest. Most of the tuners are only offering headers.