I have no answer to your conundrum, Bigkidz and what I'm about to write should not be construed as advice because I don't profess to know what's best for anyone.
For me, cost is always an issue. Does the improvement justify the trouble and the money involved? It's also one reason why I keep going back to the John Wright well. I've never paid for an upgrade (I've done three) that wasn't worth *more* than the time and cost I invested. I'm always a bit skeptical going in (i.e. what more could you do to make this better?) and so far I've always been blown away when the unit returns. I think the mods are successful because John listens to these units constantly. He helped create and refine the product. This is not his full-time job and he tends to understate the quality and impact of his work. In my conversations with him, he seems to be in pursuit of a "musical ideal" more than drumming up extra business. I trust his ears and while I wouldn't upgrade every year, I'll probably want whatever he calls a "breakthrough." I think the guy's a genius when it comes to DACS....and he's humble about it.