I bought my speed bleeder screws from SpeedBleeders.com. They are the original creator of the speed bleeder screw design and have both patents & trademarks rights. Once you get to the website, click on the Automotive Sizes link on the home page. That will take you to a listing of screws sizes with applications for various marques. Click on Mercedes and then look for an applicable model associated with Crossfire. For the NA, I used the SLK320 model listed near the bottom of that section. I didn't see a listing that would align with the SRT-6 model. You may have to contact Speed Bleeder Products directly to discuss this application. A contact eMail address & phone number is provided.

But I did notice that the Speed Bleeder sizes I bought (SB8125L - Front / SB8125LL - Rear) are used extensively on M-B models during that same time period. The SB8125LL looks like it's used for both front & rear locations on several high performance models. That screw looked to be just longer than the front screw I bought. And I just ordered the standard bleeder screws. Didn't see the need for SS.

The bleeder screws from Speed Bleeders had different hex flats than the OEM version. The OEM screws on the NA have a 9 mm hex flat; the speed bleeders were an 8 mm hex flat.

Hope this helps,