When I'm on manual mode or sport plus and really getting on it the temp rises to about 25O degrees Fahrenheit is this something i should be worried about or what is a safe temp to be at ?

 

You should check out sticky thread for :FAQ c63 w204 thread. Quite a few threads in there about cooling issues and solutions. Basically Mercedes offers a 440 cooling package which basically replaces your existing oil cooling system with that of the the black series cooling system. All members that have got this done have reported good results. I will be doing this with in the next month or so. Any MB Dealership should be equipped to this for you.

 

Better order the parts now if you don't have them, because you'll be waiting awhile. My 44O order has been backordered for over a month now, with no end in sight.

 

Most people adding the cooling package are doing so because they track the car and temps get high enough (280F range) to cause the ECU to slow the car down. 250 is not a temp that I would be worried about.