Ideal tire pressure?

I always run 28.5 psi front & back on RWD cars because I "think" I get optimal grip when they heat up midway up/down the mountain to ~32.5 psi, but then again I don't really know what I'm doing here...

It varies from car to car. But I think that near the end of the run if you have around 33 tire pressure then the tires feel really good. So I guess watch your replay and see what your final tire pressure is near the end and adjust as needed. Of course this is just my preference so I don't really know if it will work for you.

^Yeah that's the thing, I initially chose 28.5 to be my initial pressure because at the end of my run my final pressure is around 33.5 psi which is great because I remember that in FM3 the optimal pressure was around 32.5 psi. However, this being FM4, I have seen people say that the optimum pressure is really ~35 psi?

That's for circuit though right? I don't think 35 psi works as well for touge racing. With a higher tire pressure your car does feel better while your tires are cold in the first half of the new downhill. But past the hairpins you really start to notice how the car feels like a boat. With your tires being at 33.5 psi though I think it sounds good. I guess if you want to feel a difference just lower or raise the psi by 0.5 and see if you like either of those, if not then just stick with what you have.

For my tunes I don't really mess with the tire pressure. Betadood is right. 35psi will not work for Touge. I would recommend something from 33psi to 31psi.

I noticed that with most cars if you run about 27PSI front and 28PSI rear by the hairpins until the end of the run your PSI will normally be around 32.5 - 33 PSI, but it really does depend on the car. Some cars need a little bit more pressure than that, but 28.5 is a fairly well rounded starting point for a tune as far as i've seen.