New here, got some questions of a recently purchased 9k

I recently purchased a 1995 9000 CSE with the 200hp 2.3 DI turbo motor. Got a few questions and concerns. I'll be updating this thread with what I find and what I do.

First question, the car overheats. I've narrowed it down to the cooling fan. Now I replaced ONE of the cooling fan relays under the hood with no avail only to find out later that there's a second relay that controls the 2-speed function and that this may be bad. I'm going to replace that soon. Otherwise, if it's the fan that's bad, do I have to replace it with a fan of the same model, or are they interchangeable? I think I may get an aftermarket fan that pulls more air and wire a toggle in the dash if not.

Second question. How do I know if the ECU has been tuned? I've read here and elsewhere that this car uses the T5 ECU, and you have to add extra pin-outs to tune. Is this correct? If so, how do I check to see if it's been done?

Third, When the car's temp level is about halfway, it boosts amazingly. The stock boost gauge nearly touches the red. Is this normal? Once the car starts to overheat a bit ( about an inch from the red) it seems to cut boost by about half, drastically decreasing engine performance. I'm assuming that this is a fail safe to prevent harm to the motor. I'm going to be hooking up an aftermarket boost gauge to see where it's at, what is stock boost level?

Fourth, my turn signals don't work. Anything specific to look for at first? I've checked the fuse in the glove box and it seemed to be fine. Is there a relay that I'm missing?

Sorry for the long post, got some questions and I'm sure I'll have more as things go along. I'll get pictures up as soon as I can.