I have noticed previously that my S4 runs a little warmer than I would like at the track. I was wondering if going to a mishimoto 160 degree thermostat would be the right choice. I am going to be in that area anyways so i figured i would replace it. I just want to make sure it won't open too soon and lock out the aux ports.

I am running rb headers and a corksport catback if that information helps any.

 

A different thermostat isn't going to help any because the maximum cooling effect will be the same as the OEM thermostat. If you want more cooling, then upgrade the radiator. If you just need a little more cooling then a simple Koyo should work fine. Otherwise, you are going to need to move up to a competition radiator, such as Ron Davis, ARE, or Griffin.
RX-7 Store - Koyo Radiators

 

That makes more sense. Thank you for the help.

 

How hot is it running?

 

At auto-x it got to half-way or slightly higher on the stock gauge. Working on getting a water temp gauge set up for this year.

 

I solved my overheating during track use problem with the RB underdrive pulley. It keeps the waterpump from cavitating at high rpm.
Aluminum Main Pulley - Double Sheave for 74-92 Rotary Engines (All) - Racing Beat

That said, a radiator upgrade is never a bad idea, though a lower temp thermostat is just a bandaid.