The Modded forums all use Snitz as their base, so if your host is saying you'll need to make changes to Snitz then chances are you'll need to make the same changes to the modded forums.
Out of interest, what is your host saying you'll have to do to make it run under Chili 4.0 ?
I'm not a professional programmer though so the thought of having to modify large chunks of code isn't an appealing one. Does anyone at Snitz know of problems with Chilli 4.0?
How about the "grandfather" of them all (at least Crash and Images -- not sure about ServerHacker), that is HuwR's portal... his old 3.3 version was where Crash's started. Image's uses the same menu structures and icons, so I assume it grew out of Huw's v3.3 also.
Huw provided his v3.4 as an update for v3.3 users, but there's a complete "empty portal" linked in the forums (not in the file downloads area)....
I've been running it for almost 18 months, with about 5000 registered users, and it is relatively fast and relatively bug-free.... While it doesn't have all the "eye-candy" that the others do, I couldn't be more pleased with it.
Personnally I like the SH forum the best. It is well integrated with the CURRENT version of this snitz code. Although the release that is currently available does not have all of the mods you see on his site now. There should be an update by the end of the year but IMO i would download the V8 code and start out by getting that to work. In the sitenews page just remove the include for the counter and then customize it as you see fit. All of the mods that are currently active on that site are posted there somewhere.