Hehe. OK, great.
The 68030 is finally just a 68020 improvement, "fixing" some things and adding cache.
So, sure, if today a 68020 can run at 33MHz if may be faster than a 68030 using your architecture.
But, if the 68030 cache should be fully disabled you may seriously increase performance by reaching highest frequency ? (the embedded memory cache may goes defective but the CPU running well w/o)