the "ultimate" amp or preamp

Sounds like you're talking about Tube Research Labs. Point to point wiring, fully tube regulated (since 1989), best parts available. I'm not a parts man, but newer units use FIM Cable wiring, proprietary caps that are far better than Black Gate (I asked them, they'd tried Black Gate back when they first came out), special transformers (once used Cardas wire in huge torroid transformers, now uses proprietary wire. Who else tries stuff like this?).

The list goes on and on. Ask Kirk 930. He owns the huge 4 chassis 1200 lb. 800 Watt Tube Research. 96 tubes! He also owns the 400's and 300's, I believe.

I just own a pair of GT 100 mono blocks, the quality is still there, just in a smaller package.

If the so called "superior" parts used in a design have no improved sonic value compared to less expensive parts as deemed by the listening panel of an audio manufacturer, then I would have to say no.

Also, keep in mind that the circuit design of an amp or preamp is perhaps, a more important factor in determining how a product will sound than using "superior" parts.

I agree 100% Timo. Circuit design is where it's at. Many designs are built around circuits designed years back. Some use newer, proprietary circuits. Some expensive amps and pre-amps don't use expensive parts, which leaves more for chassis and faceplates. I guess it's all what you prefer.