Lets put it this way, an engine will make thew most power on the lowest octane you can run without detonation. So with that in mind race gas (leaded or high octane) will not help a stock Type-R.

The only reason for higher octane is to deter detonation and run higher compression, more boost, alot of N2O...

But many have used leaded and high octane race gas in imports. The only problem is the leaded race gas hurts the life of you 02 sensor..