I posted a link to new 40mm springs recently. There's not much between 35 and 40, so i'd go the extra 5! People stick coilovers on with much lower drop than 40mm.
u need coil compressers from ebay 4 10 squid then a set of spanners and a wrachet ser and off u go not hard job but u need an adjustable panard rod cuz one of the weels rubs on the arch , just the way they been set up so thats a must to get anyway