rattling noise when going over small bumps 1993 E300 Sportline

[Emerald]

When I first bought this diamond in the ruff it had 70,000 miles and had OEM eveything (including the rims and tires). I recently changed to a bigger rim and smaller tire. I believe the rim are off a 2005 SLK. Anyways, when I drive over pretty much any bump or crack in the road there is a rattling noise and I can't pinpoint where it is coming from... Does anyone have any recommendations on where to start rebuilding the suspension? Or if it is even part of the suspension?

Any information on this would be amazing,
Thanks!