That's what it cost them, but if you notice a couple LARGE costs should've been avoided. They paid $8500 for a donor corvette, apparently without an engine/trans, because they bought a $13k ls7 crate motor new. That's over $20k, probably $15k too much. If you buy a wrecked C5, use that engine, and the donor probably will run you $7500, but I bet you could sell a few thousand of parts off it.
There's another $10k in paint/wheels/tires. Use c5 wheels, save $2500, and maybe go all out on the paintjob, but either way, there is definitely room to trim there.
So cut $20k+ off that and you're right in line with 75% of the people I've read building them spend. They average $30-$40k from what I've seen.
Anyway you slice it, a RWD, Rear engine car weighing UNDER 2500lbs with OVER 450hp is WELL WORTH $30k, lol.