Not sure if I want to win the playoffs because if I do I will get crushed in D III
Maybe you will. Maybe you won't. Heaven knows I expected to get drubbed when I promoted to IV and when I promoted to III and somehow BB hasn't figured out yet that my team's not that good. ;) But I'd never recommend deliberately avoiding promotion - you don't need to sell out everything in order to bring in rentals to promote, but if your current roster is good enough to compete for promotion then you owe it to yourself to see if you can make it up.