What's the best y pipe to use on the Sti tmic the standard alloy one, or the origanal prodrive full silicone one off my old cooler??? Hmmm.

 

I don't think it will make any difference...

 

what year? my sti5 IC has alloy one as do newage. I would of thought this better than silicon one as it can't expand or shrink. I would recommend STI red elbow over after market silicon one as well.

 

V9, I thought that too cheers guys.

 

I sold the std sti unit with red silicone pipe and replaced it with a samco unit as the silicone one is a lot smoother in its design and is wider in diameter slightly by 3mm at the y piece junction. Samco units dont shrink & if they had the ability to expand sureley this would allow more air in to the intercooler which is a good thing.
The only other obvious reason for my decision to change over to the silicone was, the samco unit was a bit lighter and when stood in traffic for long periods the alloy unit would retain heat more than the silicone one imho.