Yep, the hotpipe connects the turbo to the intercooler. If you didn't get a front clip, or a motorset with the stock sidemount intercooler, then you'll most likely need a hotpipe. If you did get one of those two I listed, then you can use the stock piping that connects to the stock sidemount. Personally even if I did get the stock piping I'd still get the hotpipe, because it looks much better than the stock one, it's all one piece, and it matches the rest of my intercooler pipes. But I'm kinda anal about stuff like that
EDIT: Also forgot to mention, if you get an HPI intercooler it comes with the hotpipe, so you wouldn't need to buy a separate one