I've been trying to test it, but I only have access to a 'S' rank Mechanic and the 30 second Hyper buffs.
With the Mechanic card, they should last for 34 seconds if you floor it, but I can't be certain because of server latency and whatnot.
Same thing with my 'S' rank Mercedes; cooldown should be 90-->87 seconds if you floor it but again, it's too minuscule to be conclusive.
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