You have done a complete rebuild. You MUST get the car aligned. When doing the rebuild you can get it close by reinstalling various parts as close to the part it replaced. But it will not be aligned properly. This is normal. Just bring it to whatever place you trust and they will take care of it.
Here in the DFW metropex I have been using the Firestone tire store in Grapevine. $139 for lifetime alignment. We bring the cars by every 6 months.
Make sure the place you use id familiar with Mercedes and get recommendations about the place.

You can try to align the front end as Dropout has suggested, but I doubt you can do it right. the result will be a shortened tire life and poor handling.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car