HI all

can anyone help

i have a MK1 focus rs running about 370 BHP

it has uprated stat housing (DPC)
lower temp thermostat
uprated radiator (auto specialists)
stakk water temp guage

when it warms up it will be at 80 degrees
but then will go up to 100-110 even though not driven hard
if i put heating on will come back down to 80 deprees

is this right what temp should these car run saftley at

thanks