TBR passages = much harder than most MCAT passages, but Physics/Chem/Ochem are good practice (Bio is ridiculously hard!)
AAMC passages = mostly equal in difficulty
Kaplan passages = good for practice, but not very comparable to the real thing..... just use them for practice and save AAMCs for last
Basically, the closest thing you are going to get to the real thing are the AAMC tests. Some say that 9, 10, 11 are more like the current test than any of the others, but I think they were all pretty similar in difficulty.
Also, use TPRH SW for Biology passages and TPRH VW for Verbal passages. Good Luck!