Modified equipment...

Add the price of the mod to the retail price of the unit to come up with a combined price. Depending on the specific unit and who di the work it can definately add value. At the very least you should disclose the work done so that the buyer can expect a difference in performance (hopefully a great improvement!) and no that the warranty has been voided.

I recently sold a Dan Wright modded 333es. I had 20 offers in one night. I don't believe that blanket statements really can apply here. I was able to get good value on the price paid for the mods. On the topic of mods I have found them the most cost effective way to improve the performance of certain gear. I would not mod an uktra expensive piece but to get extra perfomance out of something like a rega tonearm, Pioneer DVD player or the Sony sacd players that are being modded is really were the big benefits are. The resale value of the mods will differ greatly case by case. Exchanging parts for ones of higher quality is very simple and will do no harm to the long term operation and will have incredible results for the dollar. I would happily buy any modded equipment as long as I know specifically what was done and by whom.

I would had again that some part swapping is very simple work and that some of the people that work on their own equipment can be much more skilled than those at the factory that put it together especially with the case of mass market gear like the aforementioned Sony and Pioneer. Like everything you have to make an educated decision. With lower priced gear the improvement in sound can be profound and the effect on your wallet relatively light. By being overly sqeamish you can really miss out on some great value. I know for a fact that having Dan Wright, Richard Kern or Ric Shultz work on a Sony Sacd player and the value increases dramatically, just a fact.