not really and danger, just watch the temp gauge. All the change in the cap pressure will do is cause the cooling system to allow the system to cycle the fluid in the reservoir sooner or later that it would. I think the higher the bar on the cap the longer the coing cycle, but dont quote me. I would say with your new radiator and thermostat, the opening time of the seal on the radiator cap to the fliud reservoir is irrelivent as someone else mentioned. THe higher cap only seems to help when the system is already working at its max and yours is not going to be with a new radiator regardless of the higher operating temp you are experiencing

__________________
Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red