I've used both.
For the amount of surface area you're looking to cover the spray in may be easier. It'll require a bit more prep work. But spraying it on is much easier than rolling on the Damplifier. All that said both are great products. I'd get at one or two sheets of Damplifier for each...
@Honger is 100% correct.
Hours have been spent familiarizing myself with the regs, not fun and gas would be very difficult and expensive. Diesel is very doable. But at this point is a roll of the dice, with the odds getting worse.
Now let's hear some more about this Troopy!
It'll be more difficult with the gas engine and it'd need all the California smog equipment for a 95 1FZ-FE. They will want it smogged. Diesel, pre-98 may be doable. Gas, through the state ref, I wouldn't try unless I knew exactly all that's needed.
I'd register it to your home in OK then try...