out of the few i have tried, the turbo xs (sucks), greddy profec a (doesn't learn, but easy use), blitz sbc spec s (better than the profec a), and i now have the profec e-01 which is the best of those. it accepts one greddy peak/hold guage and displays it so you don't need the guage anymore. i have greddy peak/hold egt, water temp, and oil pressure. and i have egt displayed through the e-01 with a warning light, so i don't need the guage any more. it also displays boost in any measurement, and rpm. it has 4 different guage displays and not to mention it controls the e-manage. pretty easy to use and set up. it seems to control boost far better than the others i have tried.