I'll add one more thought on the GW issue...

In the event you have to abort a takeoff at your self-determined GW of
4,000# or more and you happen to be on a short runway, the additional energy
you have to dissipate may well exceed the capacity of your brakes.  I'm not
sure if the IV's brakes are the same as the ES's (I suspect they are), but
between brake effectiveness and poor geometry between the brake pedals and
the cylinders attached to them, high energy stops are not something I have a
warm fuzzy feeling about.  Even if the structural and aerodynamic issues
weren't there (and they most certainly are) adding about 25% to the factory
advertized gross weight with the stock brakes is just asking for trouble.

I said this awhile back when a IV-PT builder said he was planning a 4200# GW
and it bears repeating: if you just put a number you arbitrarily choose on
your paperwork absent a complete analysis of all the various sturctural and
aerodynamic issues, you're essentially a full time test pilot every time you
takeoff and fly above the Lancair advertised max gross.  I understand the
need for the higher weights, but if Lancair isn't willing to test and
approve them, maybe it's time to stop and wonder why.

Skip Slater