The automatic transmission is the deal-killer.
They aren't very efficient as a rule and they're fragile.

The only way to make an modded auto Integra worthwhile is to turbocharge it, but you'll spend additional funds overhauling and reinforcing the transmission internals.

If you don't give a damn about resale value and you're mechanically inclined, it's fairly simple to convert to a manual transmission. Otherwise, I'd sell the automatic DB Integra and pick up a manual trans model.

And the weight difference between the DB sedans and DC coupes is barely worth mentioning. Both platforms are equally capable.