Problem: immediate engine cutoff after startup in heat
Solution:need new main fuel relay, heat defective

Is there any quality difference between aftermarket and OEM for this part?
Brand reccomendation?
I don't want it to crap out again so soon.

 

What year? Any CEL codes?

If the main relay is really the problem , then just resolder it:

http://techauto.awardspace.com/mainrelay.html

 

95 civic si
b18c swap

 

I don't have a resoldering iron. All that stuff would take too much time and money, a new part is only about 35$.

 

Suit yourself, but buying an inexpensive soldering gun and some solder will pay for itself when you repair the main relay. And soldering is neither difficult or time consuming.