It's been discussed at length, and you can probably find many of the threads by searching for "$2,500".
Some dealers are charging a variable premium for the first X cars. Symbolic Motors seems to be doing this, seeking between $5k and $10k for their first deliveries. My impression from talking to them is that they won't even dust off the MSRP waiting list until they can no longer get a premium for cars in stock. (Randy driving the exception, of course.)
Desert European (and I believe Newport European?) are charging $2500 + MSRP for every single car on order -- more than 18 months worth. This is the reason they had a shorter waiting list than everyone else in early '04.
Some dealers are just being dishonest and selling cars to people not on the list so that they can charge more than MSRP.
And there are quite a few dealers doing the right thing -- selling cars as they arrive for the agreed MSRP. Those dealers have very long waiting lists, as you might guess.
Galpin is charging MSRP but requiring LoJack to be purchased for each car, less than $1k.
Some dealers are selling to their waiting list at MSRP, but then any 'extra' car gets put on the showroom floor for $10+k markup, where "extra" means dealer demo, cars purchased in auction, people who drop off the list, and a number of shady deals.
In my own opinion, so long as the arrangements were made up front, honestly, and before buyer commitment, then dealer profit is something unavoidable on such a short-supply car.
Whether it's worth it or not is up to you. I do know that those $2500 will be the fastest to depreciate after delivery, but if it gets the car a year earlier...
How prevalent is this practice among Lotus dealers? I've had some hard to get cars in the past, but have never agreed to pay a dealer above MSRP, and have a rule of not even working with any dealer who charges such a premium. 
