Yeah, personally, I think that David is wrong (as I stated over on the other thread). IMHO, most people shopping for a strong driver level car aren't going to be deterred by the presence of a turbo kit (some will be, perhaps in the 25% range, but a vast majority won't be). And 95% of those shopping for a DeLorean are people that actually want to be able to drive the car (as opposed to looking for a museum piece / trailer queen / etc). Thus, I honestly don't see the presence of a turbo kit as significantly reducing the pool of potential interested purchasers.
Like any other non-providence'd car, the value will largely be determined by condition/presentation of the car and the supply/demand present at the chosen venue of sale. Having three cars at the same auction may have generated more bidders being interested in the marque than having a single car there would have, but at the same time, the perceived supply is also greater amongst those interested bidders, thus acting to effectively hold values down. Where you're competing for the attention of the interested bidders, the last car to cross the block will have a slight advantage merely from its order in the auction, as some will perceive it to be their last chance to bid on a DeLorean.
As to whether the turbo will command a premium or not - I see it going both ways. To someone wanting a more powerful engine, yes, I think such a buyer would be inclined to offer a premium for the turbo (albeit nothing huge, but perhaps $1k-3k more than they'd be willing to give for the exact same thing sans the turbo, depending upon the system installed and its condition). Those that don't care about the turbo but aren't deterred by it probably won't be inclined to offer a premium for the turbo, unless there are other things about the car that they really like/want/desire, and playing ball with the seller is the only way for them to get it.
That said, other than the turbo, there's nothing really remarkable about the car, but there are a few goofy peculiarities, a few of them I previously pointed out. Thus any bid over the $18k that the second car from today commanded, I'm going to largely attribute to the presence of the turbo, just as I'll likewise count it against the presence of the turbo should the bidding on the car fail to reach the established $18k sales price of today's second car.
In any respect, it will be fun and interesting to watch