99 e300 td

i live in the socal areas and theyre alot of hwys that travel up long hills and mountians. the outside temp is also in the 100+. for the most part the temp is pretty solid at 80c for my driving except when i hit the hills. it seems that when im in boost things really get cooking. i have a new radiator, flush, thermostat...fan clutch.. so it doesnt seem to go past 95-100c. is there anything i can do to keep the temps more level? add an autometer guage? i get worried when i see the temp guage instantly start climbing when im driving 70mph and im out in the middle of nowhere.

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1993 e300
1995 e320
1994 e320
2006 s500 4matic
2004 Jeep wj overland
2001 Ducati 748
2004 Honda shadow aero