do you guys think an MPMRI for me (say in 4 weeks and not part of AS follow up) is a good idea?
I don't know how to make this more clear. There is absolutely no use for you for an mpMRI outside of its use for a confirmation biopsy for AS. If you want to waste money, that's your decision. But there is no validated purpose for it at this point. A year from now, it is a very good idea to have one in conjunction with a biopsy
to determine whether AS is indeed your best course of action.
I have no idea what you mean by "color" but imaging at this point is not useful. Neither is genomic testing - that's just for cases that could go either way. Yours is clearly on the good side for now.
I can't tell you how rare it would be for a biopsy-detected GS6 to be T3 - much less than a 1% chance. It is only if your doctor felt a lump at the seminal vesicles or on the prostate capsule during a DRE, or saw that on the ultrasound, that such a thing would be remotely suspected. And even then, they would use a T1 or T2 MRI, not an mpMRI for the purpose.
Yes, slow it down. Decide not to decide.