I had to remove the "lip" on my 75g rim (by using a Dremel like 2tank) I've used Aqua Clear HOBs & Rena 3s (now some other brand) canister. From what I read Eheim's are not as good as they used to be. I have a small Pro Classic I haven't set up yet, but you'd need 2 probably. I like having 2 filters on most tanks so I can clean 1 & the other in a couple weeks or so.
I think they're not available anymore, but it was suggested I get H.O.T. Magnums can fit the wide rims. Maybe on the secondary market?
Used filters I'm ok with but not used heaters. Heaters are the weakest part of our aquarium hobby IMO.