Both are above average in reliability, but both are vulnerable to abuse from low budget modifications.  The FRS debuted in, I believe, 2013, which is about 10 years later than the tC, so most of them will be newer.  So the average FRS will be more reliable than the average tC.

However, you aren’t buying an average.  The reliability of used sports cars is heavily influenced by miles, modifications, and maintenance (3 M’s).  Find one that is bone stock, has a complete maintenance record, and passes a professional inspection, and buy that one.

By the way, that’s an interesting cross shop.  They are both 2-door Scions, but very different cars.  One is a front wheel drive compact coupe, and one is a rear wheel drive, lightweight sports car. Test drive both, if you can, so you know what you are getting.

The FRS is actually a Subaru. The Subaru BRZ was rebadged as the Scion FRS and later the Toyota 86. 

Which Acura do you have? Are yiu looking to replace it, or to have a companion alongside it?

What’s wrong with your Acura?

The Scion FR-S is a rebadged Subaru..

Nothing is wrong with it, I just want a toy to drive around now and then. Just something fancier. I’m aware it’s a Subaru, but I also know Toyota wouldn’t put their name on utter trash. if I remember correctly it was a joint venture? I’d probably get a manual though. Or an auto if they’re reliable transmissions.