ITRs have a long track record of burning oil. Use mine as a example... every 500 miles of normal driving I can kill almost a qt. sometimes over a qt.
On the track a 25-30 min session will kill a qt.
Then there are some like my friend Opie, He hardly burns any oil. I meen like next to none.

So what I'm saying is every time I open the garage I pop the hood and check the oil level. I'd rather take the 4 mins then blow the motor.

I have used Mobil 1 5/30 since the first night I got the car home from the dealer.
I have tried different weights of oil and if I go too thick the crossover is muted, and the power is reduced. I stick with either 5/30 or 10/30 (which ever I find). But allways M1 oil.