Simaudio i5.3 factory upgrade question

Hello,

I have a Simaudio i5.3 integrated amp and have been considering sending it in to Sim for their factory upgrade to the SE version. Apparently in the process they improve the output stage and add an improved volume control. Cost of the upgrade is $1000. So I was wondering if anyone has done this, or compared the stock unit to the upgraded SE version, and if so, whether the improvement justifies the price?

Any insights appreciated.

Thanks, Mike.