I've found that with this kind of build it is best to take your cost estimate "Odie's" and multiply by 50 percent. That will give you more real life numbers. Just take Odie's B20/B16 $1000 cost, in my experience that is way to low. Maybe for a 100k+ mile engine(s). I'd say $3k for the lump once all is said and done. For a 40K mile block and seperate 40k mile VTEC head they will need to come from Japan via JDM. And a 20B/16B is a frankenstein engine assembled from two different engines as Honda didn't make a 2L B-series Vtec.
If after a look at this X and say it is relatively well done then what he is asking is quite reasonable. On my custom '74 performance resto I already have over $25K into it in parts and engine build. Part costs can really add up when one wants the rare and best and doesn't set a spending limit!