CM-R

I just had my head recently put on and my arp head studs installed...i think the arp studs have to be re-torqued to 70 lbs correct. Could this be the problem to the oil in coolant reservoir? Do i have to replace my coolant and add new coolant in after i re-torque the head? Do i need a new headgasket? i put in a mugen headgasket and dont want to waste it...thanks for any info