Has anyone done the VTL coupling cap upgrade?

I have an 1999 VTL ST 150.The VTL website mentions an MIT coupling cap upgrade available.For those who have done it-what kind of improvement did you see?
I did it, but I did right out of the gate and had my st-150 built that way. I can't say what it sounded like before 'the upgrade'. I can say however, this is the best amp I have ever owned. And I have owned amps that were much more costly than this.