hey i have a 1991 rx7. I just bought it, drove it down here and noticed that the coolante was leaking out of the overflow tube.. would i be overheating? i stopped like 3 times on my way down and it always leaked

 

Depends.
Does the coolant have anywhere to go when it leaves the rad?.Like a Reservoir?
If the coolant is filling the reservoir and not returning,then check the hoses in between.
You just Bought it?..did you compression test it yet?

 

did u notice what the temp gauge is reading when this happens?

 

No i did not compression test it yet.. The tempature gauge was fine, I added more coolant to it and it seemed to have fixed the problem . Im planning on putting a header and get it straight pipe but I dont know what size of pipe to use? Any suggestions?

 

Don't run a straight pipe because the car will be unbelievably loud. You'll either need to run cats, or two high quality resonators. 2.5" piping is good for the midpipe.

 

well I was thinking about just putting a single exhaust, not dual ? 2.75"

 

That will be even louder. 2.5" piping is fine. 2.75 is just overkill.

Note that all single exhaust are obnoxiously loud.

 

Well my long term plan for the car is eventually swapping a 13bt so if i would use 2.75" i wouldnt have to change again

 

2.5" is fine on a 13BT anyway unless you are looking at 400HP.