changing tire profile size dangerous?

MD-370z

Hello wheel experts of the 370z forum.

I am thinking about buying track rims for my 370z that I would put on before track events and drive to the track with and back. I think I have settled on 18 inch rims with the offset of 18x10 +34. I want to run 285 ad08's on these rims but these tires only come in a profile of 30.

I used the tire calculator and it said it was too much of a difference and would be dangerous for braking. Thus in short I am asking if this is true if so, it would completly negate the reason for me getting track rims, to get faster on track and save a little cash in the long run, if my brakes dont work well then tracking just isnt that fun anymore...

So can anyone give me their opinion or experience with running lower profile tires than the sports package 19inch rays?

Thanks in advance!