Im a noob when it comes to buffers for ARs. I have a Noveske midlength and carbine AR (16, 14.5). I am stocking up on spare parts and see a lot of guys are buying ST-T2 heavy buffers for carbines so I went ahead and ordered one for my 14.5 Noveske carbine. Should I get one for my recce midlength too? Or will it not make much of a difference in performance? Also I want the best in reliability, so if short stroking may be an issue I do not want to even bother trying it. Thanks in advance...

You don't need heavy buffers for midlength uppers, especially if it is working with the current configuration.  At the most, a H buffer is all you need.

When you get the one for your carbine try it out in your mid, you might like it. Or it may give you issues from the get go, no real way to know until you do and at the worst, you're out a couple mags worth of ammo or maybe an extra shipping cost if you decide to order another one. As stated above, you don't need it, but as long as you are going to have one on hand, it won't hurt to try it.