Why do you want version 4.1 of snapdrive? It is not GA anymore.
We are using snapdrive 4.2.1 (which was GA a year ago) with SME 3.2 for Exchange 2003 on ontap 7.0.6 and 126.96.36.199 without any problems for more than a year now. I think you can also go to SME 5.0 with snapdrive 6.x.x for Exhange 2003 if you are using ontap 188.8.131.52.
Yes, you need to upgrade snapdrive and snapmanager.
You could go to highest supported version of Snapdrive/SME for your environment, but then you need to upgrade these version right after the ontap upgrade. Or you could try find a Snapdrive/SME combination that is support for both 7.0 and 7.3, but I am not sure if it exists for 7.3.