Audio Research SP-11 MK2 Umbilical Cord Upgrade??

I have heard that there are third-party manufactured umbilical cords for the SP-11 MK2 (the cord that connects the power supply chasis with the preamp chasis). Does any have experience using them or know where they are sold? Thanks!
I built some of these over a decade ago.....I spent a couple years rebuilding the SP-11, gave up and sold it....I liked the late model SP-10s and the SP3A-1 with updates better than the SP-11....
Check the Great Nothern Sound web site. I think Steve does this sort of work. I think I have seen one other source for this but I'll be damned if I can remember it.
don't bother nothing much to be gained and you will hurt the resale value
Thanks, Maxgain, I found the web site!! They do offer umbilical cord for the Audio Research preamps. They claim to improve the performance, however, Rene's comments makes me wonder if it is worthwhile at all.
Talk to Steve Huntley at GNS about it. He seems to know what the hell is going on. Also check out some of the reviews in the forum on the Wadia CD players he has upgraded for Agon members.They are all thrilled by what he does! I know for a fact that ther are simple improvements that can be made to the 11 mkII. I have an SP9 that I am souping up with great sucess! I would have Steve or someone competent to do the work, put an IEC on the back so you can upgrade the power cord and perhaps some updated caps, which is what I have done with mine and it sounds wonderful.I'm not done yet, myself,as I may change the volume control and am going to upgrade the power supply. Don't give up on your idea yet, if it is done in a profesional manner it won't hurt the resale a bit. If you get it really sounding the way you want you may never want to sell it anyway!