Regarding "Franks":

(Frank = watch made with parts from other models made by the same company(could we call this a prototype?), or another company).

I wouldn't call a "Frank" or "Frankenstein" a prototype unless it was created by Heuer in Switzerland before or during production of a model. This would preclude watches made of spare components being labeled as "Prototypes". Those types of watches are "homework" or "Mechanics/Watchmakers Special Editions" but not Prototypes in my estimation.

If the "Frank" looks and work better than the "original", would you buy it?(consider original parts and a great service in the watch)

The answer for me is... Depends on the circumstances.

There is a certain stigma with "customized" watches amongst many collectors. Most collectors look at them with a certain disdain... So while it's accepted even celebrated when people customize cars, trucks, motorcycles, etc. in many instances, with watches it's not usually so.

While there would have to be extenuating circumstances to get me close to pulling the trigger on a "custom" watch, I can not say I would never consider it.

I've long sought a non-rare, non-historic Speedmaster moonwatch that was in dire need of a new dial to appear on the market at a reasonable price so that I could replace the bad dial with a non-correct Mark II dial for my own enjoyment. I would probably never sell the watch, and if I choose to part with it, I would either replace the dial with a proper one, or fully disclose the facts of the matter. After all once one purchases a item it is theirs to do with what they wish to, although I respect the right to encourage the preservation of rare or historic examples for the sake of originality and "for the record".

But I would not personally customize a rare example or one with a certain level historical significance unless it was easily reversible (straps, casebacks, etc.). But a damaged or "basket case" watch... I wouldn't have many qualms about customization.

I had the leather strap on my TAG Heuer 2000 Professional, automatic replaced by the strap of the Carrera (one with the holes in it, I just love the look of that strap!)by ProTime (TAG service), does that make my watch a "Frank"?

Nope, I don't believe so, because it is easy to replace the custom strap with the original. It is the horological equivalent of putting custom wheels on your car. If you retain the originals, you can restore the car to it's pre-customization configuration in short order. Not a frank in my opinion...

Even if it looks better than the original?

In fact I am forced to do this sort of thing often, because I have large wrists and most straps simply do not fit me properly and the OEM either does not offer links or longer straps, or prices them at prohibitively expensive levels.

Changing straps is about as significant as changing the wheels on a car. If you leave the Carrera Strap on the watch you couldn't list it as "all original" unless you swapped the strap back.

I remember reading somewhere that Chuck change the dial in one of his Heuer Pilot watches (Am I right Chuck?)

Yes, I did have Pro-Time (LVMH/TAG-Heuer's service center in the US) do this.

and the service was done by Heuer,

Pro-Time, which is essentially the same thing. LVMH's Service facility in the US...

does that make his watch a "Frank"?

Interestingly enough, in this specific instance it would NOT based on your stated definition of a Frank. Why? Because there is no case reference difference between a 130.006 Black Dial, and a 130.006 Silver dial. So what I had done was to have the dial of my 130.006 replaced with a new 130.006 dial. The dial original to the watch was silver, the NOS replacement was black, but both are 130.006 dials.

However, if there was a different case reference, say 130.006-S for Silver, and 130.006-B for Black, it would be a Frank at least in the literal sense...

Best regards,

Marcos

All of this is just my viewpoint. I'm sure other's will vary. I hope this helps...

-- Chuck