Could someone tell me the diferinces between the Sig Kougar mark III and King cobra, both are nice looking airplanes.

Tks.

The Kougar was nominally a .40 size plane (but we all used .60's, of course), and was geared a bit more toward the "sport" flyer. The Kobra is a .60 (which probably means a .90!), and slightly geared more toward the aspirational aerobatic flyer. Both are pretty close to each other in flight behavior, so let appearance and size drive your decision.

Ahhhh, thanks
Any ideas how the Kobra will handle a 91 surpass?

I have the Kougar set up with a Scorpion 3026-10, 4S pack and 11X5.5 that flies fast enough for me. I could use a 5S pack and 10X7 prop but it gets too fast for my comfort range. I used to fly it with 16 round cells and it would still haul.
When I built mine, I covered it with Ultracote brushed aluminum which was a mistake as it would blend into the background and disappear kinda like a Romulan cloaking device. The brushed aluminum looked cool but made for difficult flying.
Last spring i removed that old covering and re-covered it to look like an Air Force trainer with safety orange and white. Much easier on the eyes to follow when it gets out there a bit. Oh yes and I bought some Robart strut covers which gives it a bit more realism.
Good luck on what ever you choose. You will not be disappointed.
I came across a good deal on a King Kobra at Toledo last April for $85.00 or best offer and passed on it for a couple hours, when I returned to make a deal, it was gone. I later saw it behind one of the tables on the mezzanine.....for $125.00
Oh well...win some , loose some.

Kobra is .20 size
Kougar .40
King Kobra .60