James,
When these were on Petes car, I noticed that the spool from the second turbo felt like the same 'hit' that you get from a j-spec thats decatted.
Compared to my j-spec auto I had, I'd say they were a lot better, and safely producing the extra power without the downside of wondering how long the blades would last. A double benefit if you like
Anyone considering these should bare in mind that they'd be great as a spare set of twins - especially at this price, with the bonus of uprated internals.
Pete's would've kept these running for a lot longer, it's only that a combination of me /my single and Paul able to offer a great deal on a single kit that Pete's getting rid of them .