[WMichelsen]

I understand the purist perspective. But, I don't agree with some of the other points.

It says the kit comes with the engine already. So, $18K is total, DIY install, plus probably a couple K for incidentals. Let's say $20K. ... for 300 HP.
You have modern reliability, easy/inexpensive maintenance/repair, etc.
And, you still have the original removed engine to reinstall later, rebuild, or sell as a core.

I haven't done it (yet), but I understand a basic return-to-stock DIY 911 engine rebuild is about $20K. Stepping up to get 300 HP adds $10K to that. (Please correct me here ... it's in my future)

So, it sounds like a totally viable and reversible way to get a 50% performance boost for relatively cheap.

Of question.. how much has it been tested in real-world extremes? Does it have enough radiator cooling stuck in traffic @ 110 degF?