The 4033 v. v67 aside, I HIGHLY recommend against trading your SM58 for the 4033.
Granted, you may only need a 4033 for a specific vocalist who you will always mic. However, the SM58 is extremely versatile and is almost a must have in your mic cabinet. (I say this only because it is so close to a SM57, which is an actual "must have" mic).
As a dynamic mic, the SM58 is useful for mic'ing speaker cabinets, drums, even vocalists, etc. In a functioning recording studio, you will always need a decent dynamic mic.
SM58 and v67 vs. v67 and 4033?
I'd take the SM58 and v67, if only to get the SM58.