As Stu said, bearing in mind the high ambients on the test day, they all did well.

Worth noting that the genuine RS500 item is the oldest design of the lot.....Designed in 1985/86 = 18 years ago, using the very best core material/end tank design methods available at that time.

Surely it should come as no surprise that the newer versions would improve on the performance of the original, given that 18 years have passed?

Edited to say that i'ts no coincedence that the NEWEST I/C to the market-place the Pro Alloy product, did the best....Big up Wayne