Here is a quick build list for the engine/trans in the video:
stock 2jz: 500-800
2j to th400 bellhousing/converter/etc: 1500ish
th400: guessing 1-3k built
cams: not sure about it, but guessing 400-800
pistons: 500-800
rods: 500-800
valvetrain w/ headwork: 1-2k
my rough estimate for just the an engine to run 40-50 psi along with the th400 comes in around 8-10k, not including the car.
Yes it's would be a ball of fun, but you could easily hit a 9-10 second quarter by adding 30 psi, head gasket/studs to a stock block 2j by putting it in a car that weights 2500-2700 pounds at most. Their are several 2j 240sx's that are running 9-10's by even using beefed toyota a340's series trans.
At the end of the day, I am not going to say that 2j is better than the ls. It comes down to for me what you are good at building and what you can get parts for.