For lowering opiate tolerance, I might suggest low-doses of DXM, but I would not be so inclined in your case for a few reasons. If you were to do a daily regimen of DXM, you would want to use a very low dose, as DXM is potentially neurotoxic and 90 days is a while even if you are a taking a dose you cannot "feel". But, I do not see it helping that much with amphetamine tolerance, and I think it could backfire because of the constant activity DXM would be causing with your dopamine and serotonin levels, even at a very low dose. I would frankly advise to steer clear of it completely, I just don't see it benefiting you over other methods. The number one thing to do for amphetamine tolerance and protection of neurotoxicity is abstaining from amphetamines including MDMA, as many people forget it is an amphetamine. Other than that I would most certainly suggest magnesium as a supplement. It should help. Nine months is not a short time to be on amphetamines, but a three-month break should allow the amphetamines to do their job much better come the beginning of fall.