well that pedal you have ,I also have and it sux and the preamp you are using I have but the rack mounted version and it sounds very good.I dont use a distortion pedal cause this thing has enough of it own distortion(try holding the tap button and turning up the drive this will give you more distortion on the pod),if you want huge sound you are going to pay for it.You will never get the same sound out of a pedal as an expensive rack or floor unit.
Warheads are nice but expensive and I dont think you will get a neo classical tone out of it, more the neo-thrash tone of Dimebag.
here are 2 pics of my rig,I can get any tone I need,but most of it comes from the pod pro.
you said that you got a handmade speaker from ebay well that could be your problem cause the box itself has to the right size and everything,its a science of its own(mesa boogie has custom made speakers from eminence, about $100 or so per speaker)
hope i could help you a bit.