Good job! I love taking Porsches by surprise too.
You should get some kind of data logger so you can see the g's you are pulling under braking and in turns. This will help you see where you can get faster. If you are only pulling .8 or .9 g's in turns then you know you can take those turns faster. If you are only pulling .5-.6 g's under braking then you know you aren't braking hard enough or you are braking to soon. Full gas, full brake, everything else is a waste of time or so my driving instructor use to say. Now obviously that isn't always the case, but try to keep from lifting before braking zones. Go straight from full throttle to full brake in those areas. If you listen to the audio its hard to tell, but it seems that you do that a few times in the same spot.
All in all very good and that track seems wicked fast. Fifth gear in the straights?! You have to be doing like 135/140 at the end of the straight. It's no wonder your brakes hate you!