You can get stock springs from any motor factor, alternatively I find eibachs springs are very good for maintaining ride quality as long as you dont have stupidly harsh dampers which you dont. As for buying them from ECP, good luck finding which ones you actually want, their online site is fookin awefull in terms of the product descriptions adn they only list ones for a 1.8 engine which could be anything from a driver to a valver, both of which have different spring rates.
I had Mk3 VR6 eibachs on my Mk2 8v Gti with Koni adjustables and they were still fine with the damping turned down, even if they made the front end sit up like a motorboat lol. Before you ask, I wanted the dampers and they came with the springs secondhand at a bloody good price hence the use of the VR springs and no, I dont know why the person I bought them off had VR items on Mk2 dampers unless they had a VR's Mk2 lol.