It's all depends on what you do to your rex. IMO 2nd gen stuff is harder to come by but, FD parts are easier.

If you rebuild your motor yorself it's gonna cost you about $300.00 and buying one will be about $1,000.

I don't see rex as a money pit, though.

It start to getting pricy when you begin modding to your liking just like any other motors out there.

I dont know that you can rebuild a blown motor for $300. when a motor blows, you loose at least 1 apex seal, and at least 1 housing. the housing alone is at least $300. not to mention all the seals and gaskets you would have to replace, just to put the motor back together.
you can buy a used JDM motor for about $800, thats probably the cheapest way you could go.

try to find a 13brew engine for 800.... turboII's are hardly found for 800... I've rebuilt plenty of engines using same housing it came with.. turbo engines are a different story as when an apex seal goes there is considerable more compression than a n/a motor, but it is still possible to not damage your housings..

well I dont count NA motors...lol
you can get all JDM motors real cheap all you have to do is go to an auction. companies that import motors hold auctions here in the state, open to the general public. I use to be with cartune texas, and we would get 3 SR20det clips for a grand. they do these auctions once a month or so, on the west coast, they acualy post adds in auction papers

But obviously the TT FD engines don't last as long as the n/a FD engines right?

there is no N/A FD engine

Non turbo 3g RX7's. Those are N/A.

There are no non-turbo 3g's. None in the US at least.

would be cool to have a N/A bridge ported FD

lol. If there were any N/A FD motors I'd love to buy one, put some spacers in it and put wide rotors in it. Bridge port, then probably slap a S/C on it.