Sonic Frontiers Hybrid pre amp question

Hi all,
I have an SFL-1 wich uses just one tube, the tube I am using is 1 of a matched pair of the 6201 nos tubes valvo/ Amperex from the Herleen plant in Holland from 1961.
What I am curious to know is, when using a one tube Hybris how much of a tube sound does this pre offer, is it somewhat of a middle of the road result from the hybris design, and what are this designs strengths and shortcomings?
In short how does this compare to tube pre amps with 4..6.8 tubes.
Also in close this has always seemed to be a peice of gear that was well respected so in the spirit of fun how much would it take money wise to top this pre amps performance? thanks for your time
1.Change panasonic 100uF in PS for Solen 75uF @ 400v bypass with MultiCap 3uF. $20 parts
2.Coupling caps 3uF and 1uF from MultiCap to Auricap or what you like (AuriCap is my chois). $40-50 +
3.Diodes in PS for beter ones $10-15
I have an SFL-1 signature and I bought an upgrade kit from Chris Johnson from Parts connection, the upgrade was amazing. If you would like I can send you the parts list and you can check it out. Just send me a private message and I will look for it.
And to answer your question, the sound of this hybrid preamp is a real tube sound, of course it has only one tube. So it is a real tube sound but with some of the detail of the integrated pres, I always felt that its a terrific combination. The one tube is in one side an advantage, because changing only one tube you can tune its sound. I use it with my Conrad MV50 and a pair of Tylo Reference Monitors and I love the sound, warm, great midrange and a lot of extension in highs, the bass is not so good but thats the MV50.
Hope this helps
Thanks Alan for the reply.