I am sure there are more than a few write ups on this. Some probably more helpful than mine. But here is a link to a post I made with some pics of the SL55 intake on one of my SLK32s (which is essentially identical to the SRT-6).
Does anyone have a link to a detailed DIY sl55 intake upgrade? - MBWorld.org Forums

If you are all about performance and you want the Best set-up, buy one of Rob's (needswings) well-made intake set-ups ...but, if you like the stock look, the SL55 intake is the best way to go in my opinion.

Cheers,
Chris.