I pulled off the hose that connects the metal coolant return line to the block. You can see it here. It's connected by little spring clips that were very difficult to get. It took a lot of patience to get out. I can't imagine doing this at the track when the motor is hot and you're short on time.
The rubber has hardened, and the weave is starting to stray. It looks good on the outside, but the rubber coating is really just cosmetic. It's the weaving inside that gives the hose its strength and structural integrity.
If you're curious where it mounts, look at the picture below. The red line is that rubber tube there. It mounts up to the block and connects to the blue line, which is the turbo coolant return line. If you get the Taka S13 T25 kit, it replaces both the rubber and metal lines.
