From my experience and point of view, marginal increases in cost can make a huge difference in the final result.
Experienced tube builders already know this, but a novice tube builder may not.
For example, you can build an all new Dyna PAS3 clone for around $450, and have a nice decent preamp.
It would be about equivilent to buying a new product for around the same price.
On the hi-end, you could get the best of all the parts available for a total of around $800, and wind up with a preamp that not only looks great (professionally finished custom front and rear machined/engraved panels)
but with the inner circuits and sound that compare to commercially available new products selling in the $3000-5000 range.
The LA12 line amp and the PH12 phono amp are gonna get you there, and can be built as separates or all in one larger case. I hope to have kits for these available by mid-November.