(faster and cheaper than a SRT-6! at least it was cheaper when they first came out)
It's not really cheaper at all. The $22,995 price for the Renntech 404/410 performance package is with an existing vehicle, but the SRT6 lists for about $10,000 over a Ltd. Adding the Renntech brake and suspension packages comparable to the SRT6 makes the difference in favor of the SRT6 even more dramatic, it seems to me.