Tube rolling Herron VTSP1A preamp?

Hi guys,
Well I love my Herron, it's proven a more than worthy replacement for my Supratek Syrah. Now I'm aware that Herron recommends strongly against deviating from the stock, factory provided tubes. However I also know there are plenty of you degenerate tube rollers out there, has anyone tried this and with what results? I recently put a pair of Siemens EC88's into my cd player with excellent results, but the price of a quad of Siemens is proving to be cost prohibitive, I just bought a new condo, and difficult to find. So my question is this, up to about $150/quad, is there a worthy 6922 out there that will outperform the stock Sovteks? Or should I wait until I can blow $400 or so on a quad of Siemens CCa? Or should I heed the manufacturer and stay stock. Rest of gear is Tube Tech cd, Rega P3, Camelot phono, KR Audio Antares V300 amp, Alon Lotus speakers. Thanks!
Did you read in Karl Lozier's review at why Keith said he didn't encourage swapping the stock tubes? It seems like a pretty valid reason.
I did read that review, I just thought there might be some owners out there who had rolled tubes anyway. Just curious, you know.
The only people I heard of who rolled their tubes put the stock tubes back in pronto.

This is situation where I'd take the manufacturer at his word (and I normally hate stock 6922 Sovteks). Keith does voodoo with these things. It ain't worth the money to experiment. I know it sounds counter-intuitive to call a tubed preamp "plug 'n play", but that pretty well sums it up. The preamp isn't picky about cords either.

Leave 'em alone and enjoy this great preamp.

BTW, I have Alons too (Vs) and find the Herron gear synergistic with my speakers - I use Keith's amps as well.
I was tempted as well in trying other 6922s on my 3 months old VTSP-2 but so far with the factory fitted tubes it just sound so right.

Being a "Tweaker" I could not resist tweaking all of the Herron's 6 tubes with Herbie's Hal-0s. I can now hear more details & less sibilance particularly on female voices with the "tweaked" Herron. The Hal-0s is a must audition......
I had one and it is a FINE, FINE piece. Tried rolling, too. High-end Teles, Seimens, etc. etc. The only quad I found that sounded any better than the stock tubes was a quad of Rathyeon-badged tubes that I believe were US Amperex. Ipy's suggestion of the stock tubes with Hal-O's are just what I settled on. And happily. If I had not gone to a passive linestage, I'd no doubt still have the Herron.
Wow, nothing for 5 months and then 3 posts in 1 day! Thanks guys, based on this and other stuff I've read I'm staying stock. Unless someone tells me about some can't miss wonder tube that's relatively affordable. Until then...