On the Kia 3 were fairly easy - ish to get out, 2 of them did require an injector removal kit (usual auction / buy it now site - £45) with a slide hammer though, but 3 out in one evening. They are Delphi, with an M14 thread on the top of them so a doddle to get the adaptor on. The 4th one however, the one with the ton of leak off naturally, took many attempts to eventually get it out, and going back downwards a little (which I really did not want to do given how much effort it took to get it up the first 25mm) and soaking it with WD40 hoping some would get down the sides. And i managed to strip the thread on the adaptor of the kit! I'm stronger than I thought but they sent a replacement bit PDQ so Friday evening I got at it, up, down a bit, got frustrated and angry gave it everything I had and it started to finally come up a bit more. So after a breather more welly and out it came, at last. One of my neighbours is a mechanic (not too generous with his time though - disappointing after I've fixed his boiler a couple of times) and lent me a little wire brush device to clean up the bore for the injector body. It has a rod with a brass ferule on the end that fits in the nozzle hole to stop crud ending in the bores. So far so good, it keeps starting up really easily at the minute, but I'm never too sure I'm out of the woods till a while later! Doesn't spew black smoke like a Klingon cloaking device now either