180 deg or 192 deg thermostate....

[Fried One]

Hello Guys,
I'm running a 180 deg thermostate in my 92 lx. I do believe that this tricks the computer to run a little richer. My car is quite heavy on fuel. I was wondering if it would be better to replace the thermostate with the stock 192 deg one. I am thinking that the little bit of performance gain if any is not worth the extra fuel usage. Also would it not drive better with the 192 deg thermostate. My motor is mostly stock with a few power adders.
Basically no internal engine work. Full exhaust , headers, cold air induction. Bigger rad. Also running regular gas with stock timimg. What are your thought on this.