We looked for LS trannies for a while. Weren’t able to find many that were less than $300. Combine that with the fact that the B18 in the car could really use a refresh (its not fucked, its just pretty tired with your typical old honda mediocre compression and slight oil burning) and the sub-100k D-series motor and trans that were sitting in the corner of the garage, and most of the parts for the swap are already there.
Integras did come with D-series in them from the factory in other markets. It will absolutely move the car without any problems.
Once this is up and running and he’s been driving it to work for a while (read: has money again), will probably do a vitara build and drop it in.