heatercores are nearer the dashboard (they're used for transfering heat into the car) they are smaller and usually better performing compared to rads (for their size)) the best ones (for pc's) are Cavilver and Nova heatercores -since they are copper -for best heat transfer, and have 1/2 barbs meaning no/ minimal modding
^you can pick them up at scrapyards, or from ebay pretty cheaply
nope, aquatics-online are cheaper £42 inc vat + p&p for the 1250. wheras pclincs is £48 + p&p
dont have links for swiftech kits, will look into it in the morning for you. they just are respectable, and have similar performance to the dangerden kits.