The design is by Welter Racing, who's cars have always been ..distinctive:
They were also quite slow even before they added the improbably large air intake, so I don't have a whole lot of confidence in their design.
As for the rest of testing:
Audi vs Toyota - 1.3s per lap might sound like a lot in F1 terms, but one has to remember that La Sarthe is about 2.5 times longer than an ordinary circuit, so you're looking at a gap more like 0.5s at a normal track. This is the sort of gap that can be overcome over a 24 hour race, to take the recent Peugeot vs Audi rivalry:
2007 - Peugeot qualify 0.55s faster than the fastest Audi and 1.9s faster than the winning Audi.
2008 - Peugeot qualify a massive 5.3s faster than the fastest Audi (which also won).
2010 - Peugeot qualify 2.2s faster than the fastest Audi, yes Peugeot lost through reliability but the Audis were able to run fast enough and consistent enough to force the Peugeot's to push beyond the limit of the engine (they had 3 identical engine failure from 4 cars.)
Assuming the 1.3s gap doesn't increase between now and the race itself, Toyota are "within range" for an upset, unfortunately for them if you were to bet on one team running the perfect race, you'd bet on Audi, especially with four cars.
Deltawing - A bit disappointing but not disgraceful, they are right in the mix with the slower Orecas and HPDs, and well clear of the GT field, perhaps more surprising was the apparent pace of the Morgan/OAK Pescarolo, they've been midfielders at best in LMP2 for the last few years, their results usually come from reliability rather than pace, so this is very encouraging for them.
"Well we've got this ridiculous situation where we're all sitting by the start-finish line waiting for a winner to come past and we don't seem to be getting one!" - James Hunt, Monaco 1982