The first post will help you find the location of your MAF. On my 1999 it was in the lower position, not sure where it is on the 2000 models but the link has a picture for both possible locations:
You can use this video as a guide for the removal part:
Mercedes Benz SLK 230 MAF Removal and cleaning - YouTube
In the future, I suggest you use CRC Mass Air Flow Sensor Cleaner instead of electrical contact cleaner. Also if cleaning, remove the sensor (insert) from the housing.
Once you get the sensor+housing removed (about 2:20 in the video), it is going to one of two things. Either you will be able to purchase the sensor plus housing or you will be able to purchase just the insert. I used to get my MAFs from autohausaz. They used to sell just the insert for around $100. Looks like they have the entire sensor plus housing for sale now:
Your Parts Search Returned 2 Part(s)
I would bet you have the Bosch unit in yours but double check before ordering. So it is just a case of replacement if you go this route.
If you find just the insert for sale, do the following:
You need to remove the actual sensor (the insert) from the housing. You will need a set of torx security bits. You can pick them up at any parts store or even Harbor Freight. The HF ones will not last long but there are lots of bits in the kit. They come in useful sometimes. So undo the 2 torx security bit screws holding the insert in. Remove it and replace with a good insert. Put everything back together.
Be sure to check your air filter while you are at it.
DO NOT GET AN EBAY MAF!!!!
Anyway, good luck. This is a 10 to 20 minute job. I am assuming your Check Engine Light is on. If you have access to an OBD II scanner, you can have the codes cleared with that. Alternatively, just can disconnect the battery for a few minutes to clear the light. Just be sure you have radio code if you do that. If neither is acceptable. The light should go off after a little bit.