hello fellow ford modr's

picked myself up some underdrives for a great price was just wondering if you guys would be able to answer a few of my questions?.
can i install them myself if so whats needed, also has anyone got them on there ba xr8 if so are they a worthy mod
thanks all cheers steve

im going to get a set put on wen i get my oil pump gears done i suggest u do the same i heard a few rumors they give way with this mod

hi guys got my underdrives on sat put them on today and wow prolly the best results i have had off any bolt on mods!. really can feel them up above 3 thou extremlly happy its def a great mod with good results and not to pricey