There is a world of difference between the SFP-1 in any version and my unit, the Phono 1. In addition, I have the SE+ upgrades, which includes new PS lytics, new Vishay resistors, and New V-Cap TFTF and OIMP coupling caps.
It appears my budget has been increased to the 10K area, so I'm sure this is going to murky the waters somewhat.
I had the Sonic Frontiers Phono 1 and I put every shade of lipstick on that Pig and even sent to Chris Johnson for cosmetic surgery with every upgrade possible. Countless dollars spent, dozens of tubes rolled and in the end, it still was a just a Pig.
With a budget of $10K, I would highly recommend investing some of that money into a new phono stage as that will give you a greater return on sound improvement than changing out the excellent FR66s.