Diagnostics

Greetings, new on here just looking for any of your oppinions on diagnostics software/computers. I am looking at setting up a workshop sometime in the near future and was wondering what you think would be the best route to go down. Id be doing work on a fairly wide range of diggers but mainly hitachi. There would be a few customers of mine with daewoos jcbs and kobelcos also stuff like volvo a40's and agricultural tractors and trucks. I dont think there is any diagnostics equipment avalible that covers all makes of diggers both engine and hydraulic? I have found a couple here that will do most machines engine/diesel diagnostics i reckon. It also covers trucks aswell which would be usefull. Just wondering has anyone on here used or seen either of these computers or what do you think would be the best option for me? http://holyhands.en.alibaba.com/pro...ing_instrument_excavator_diagnostic_tool.html this is the one i seen first and it seems to cover diesel/engine diagnos for most and on some makes it does hydraulic diagnosis too. Im afraid thou because i cant find much info on it or how if even possible to update it. http://holyhands.en.alibaba.com/pro...ing_instrument_excavator_diagnostic_tool.html this is the 2nd machine i came across its diesel diagnostic only from what i gather but seems to be a bit more common. Any info on either of these or any recommendations for anything else would be appreciated