I was told the standard one for the 110 bhp tdi leon would only really support 170bhp so I couldn't see ours supporting 180 bhp. Apparrently longer tubes give potentially better cooling. There is a replacement SMIC on ebay that is the same size as ours but a lot thicker. It might be worth a go. I'm currently getting a spray set up together at the minute to bring the temperatures down, I've really only got the temperature activated swithch at the moment. Do a bit of digging on autospeed.com and it gives a lot of advise and research to get a good set up.
Have a quick look at your other bushes to check that they haven't perished. You'll notice more benefit when all the bushes are matched, arb bushes can have a huge affect. Plus a kit with the whole lot may be only slightly more expensive than what your planning on doing at the minute.
The 2 wires on the fuel pump wiring harness sounds similar to what I'm going to do. Mine isn't the evry mod though, my resistances are much
lower which wouldn't work. I gather that it's a bit crap anyway. I had the homemade tuning box on my leon which worked a treat. I haven't done it on the cordoba yet as I need to check my oil pump and pick up and get fresh oil in her and straighten out my intercooler fins and replace the v belt. Hopefully tomorrow.