Fan speed mod to Diamond Radeon HD 2600xt: Is this legitimate + safe?

Last week I sold a Diamond 256mb GDDR3 PCI-E Radeon HD 2600xt on eBay and in the auction I clearly stated that I had done a mod on the card to reduce the fan speed to lower the noise level of the card (originally, it was a horribly noisy card, as loud as a hair dryer on low setting, which is typical for this brand and model card). I also stated that buyers should ask questions before bidding and that any information they acquire after the auction ends will not excuse them from completing the transaction (my standard auction terms – I have 100% positive feedback in over 50 auctions as a seller and almost all of that feedback reveals that I go out of my way to make sure that each transaction is an excellent one for my buyers, much more so than the average eBay seller). My buyer just e-mailed me and wants to back out of the auction and return the card for a refund; my auction rules state no returns. The buyer did not read my auction listing closely and did not notice that I stated I had done the mod. He also claims that he smells a burnt, electrical odor that he has concluded means that this video card overheated and he believes I fraudulently sent him a fried card misrepresented as a working card. He refuses to install the card and see if it works because he claims he is not willing to risk this card burning up his computer.

Nothing could be further from the truth – this card worked perfectly when I pulled it from my computer two weeks ago. I did not notice any sort of smell coming from the card, let alone any evidence that the card had overheated, which it most certainly did not. I am the card’s original and only owner and only had the card installed for just a week in one of my HTPC’s before I got bit by the upgrade bug and decided to go with a new Radeon HD 4650 instead. The card has never been overclocked and has only been run under load twice when I briefly tried it out with Titan Quest (which it played very nicely). After I did the fan mod, the card idled between 35C and 40C and under load, it never went above 60C, which are altogether acceptable temperatures for any modern video card.

Here’s what I did to modify the card (quoting an e-mail I sent to the buyer a few hours after I shipped):

As I mentioned in the auction listing, I did a mod on this card, by connecting the power wiring on the card's fan directly to a molex power connector coming off the power supply unit, to reduce the fan speed and make it a whole lot quieter. To do this, I very slightly bent the two connectors on the ends of the power wires to remove them from the pins on the video card. If you don't want to do the mod and are fine with the fan running at 100%, you can put the two connectors back on the pins on the video card's board, which are located directly above the fan unit if you are holding the card horizontally with the PCI-E connection on the bottom and pinch them closed with a small needle nose pliers or sturdy tweezers. If you want to do the mod (which I highly recommend as it really was incredibly loud with the fan at its original setting plus it only raised temperatures 1-2C by lowering the fan speed), the directions are as follows:

Stick the red fan wire into the yellow (12v) wire's socket on the molex connector, and stick the black fan wire into the red (5v) wire's socket on the molex connector, which will give you 7 volts at the fan. The fan wires can be teased from their plastic housing, complete with the metal plug on the end, by pressing in a tiny metal tab. Those springy metal connector tips make a great friction fit within the molex power connectors (which are hollow). You may want to wrap some electrical tape around the molex connector to make sure the fan wires stay in place. Don't connect fan red to black (ground), and fan black to yellow (12V). That would have you running 12 volts into your fan with reversed polarity.
So, here are my questions:

1) Can you see any problems with the mod I did on the GPU’s cooler? Is this a legitimate and safe modification? It certainly isn’t irreversible.

2) Would you agree with me that the temperatures at which this card was running are entirely in the normal range and would not have burned, fried or otherwise damaged this video card?

3) Have any of you ever noticed an electrical smell coming from a perfectly functional video card? I’ve had a number of electronics items over the years that had an electrical smell yet worked fine.

4) Although this is a moot point since the video card arrived in the buyer's hands undamaged and in as-new condition (but for the mod), hypothetically speaking, could an overheated/fried video card burn up or damage a motherboard or other significant components in a computer? Seems like it just wouldn’t produce any display. If a card actually had overheated, would it be safe to plug it in and see if it works?

Thanks for your help – I really appreciate it.