Date registered: Dec 2005
Vehicle: W211 E320 Bluetec R129 SL500 - $1300 car ........ Ford F350 6l
Location: CA Bay Area
Mentioned: 9 Post(s)
Quoted: 1119 Post(s)
You should have original tire pressure listed on the fuel door, or on driver door pillar. For different tire height, you still use the same pressure unless the tire manufacturer advise otherwise. I believe you car originally had 195 wide tires, so with 205 you could go with slightly lower pressure for comfort, but than higher pressure gives better fuel economy and usually better tire wear.
Is your car ABS equipped? If yes, different tire diameters can create some issue, but you would notice that by now.