Was under car other day noticed black oily substance on a pipe drivers side. Its not dripping just bit gundgey, is this the stuff that i read gathers in the smic which is why you clean it or should i be worried? Only got car in december and like to read up on stuff before i randomly take bits apart so if it not important i rather leave for a bit.

Yes, that's the oil that collects in the inter-cooler (and the boost pipes.) It comes from the PCV system (rocker cover vented into intake pipework). If you want to stop it search elephant hose mod. Combined with soot from EGR system, it forms a horrid black gunge in EGR valve and intake manifold.

Got some free time this weekend will have to find the guide on cleaning it. And look for mod later, does it effect performance?

Doesn't effect performance. Might even improve it very slightly due to the fact there's no more hot oil vapour going into the intake.

If your IC is anything like as gunked up as mine was, cleaning it should have a noticable effect on performance