I would say eliminate it - with that many variables changing on the engine, it's probable that the stock knock sensor will be easily confused.
But for tuning purposes, I think you'd want something rigged up, especially if you're street tuning. A J&S would be ideal, of course, but check out
this page - a DIY knock detector for about $15. Obviously not any good as a permanent knock prevention system, but would be handy for tuning.
