Eh...Deluge has made a number of changes to libtorrent that aren't replicable solely by config tweaks. Such as lying about what pieces that client currently has, lying about connections and others in order to get the tracker to assign more peers and increase per-peer connections. Deluge also abuses the ever-loving-crap out of memory, since it doesn't use the system memory manager and, at least last I looked, their home built caching system was horribly broken (that is, they goto-failed their own manager) which leads to horrible flush to disk scenarios that kill speeds.