CB72 - do you really have a 22mm bar in the front and rear?
Your snap oversteer at 6:30 looks to be due to the steeply off-camber nature of the corner. From other laps it appears the road falls away quickly at track-out near the curbing. Since it looked like you were on the throttle, and still cornering hard at track-out on that lap, I would call that oversteer a result of the nature of the track.
As far as your understeer goes at 9:10, that is a long sweeping corner. The NSX is a well-balanced car and responds to your inputs. If you are on throttle, you unload the front tires and the car should understeer. If you're off the throttle or trail-brake, the car will typically turn better (up to a point). Try carrying more speed into that right-hand sweeper with some trail braking and coasting, then pick up throttle later in the corner to minimize your understeer. In general try trail braking more.
Also have a look at the driver development article I wrote on car control:
http://www.motoiq.com/MagazineArticles/ID/3519/DRIVER-DEVELOPMENT-Car-Control.aspx
Car wise, invest in a probe-type tire pyrometer which will tell you what you need to do with your alignment. Due to the really low front roll center, NSXs need a lot of front bar to reduce roll.
Billy