241 gauges?
I only planned on buying 4 Defi's originally, Boost, Oil Temp, Oil Pressure and EGT, but that was because I planned a powerful engine and planned to put it on track and give it some abuse. I think too many gauges for the road is overkill, especially on a standard ish car, but they are handy at times. I wouldn't bother with EGT's, as there is fuck all you can do with them anyway, and I never have a problem with them, the gauge is just handy for mapping.
Have a look at SPA's site, they do different combinations of gauge, but I would suggest Boost, Water Temperature, Oil Pressure and Oil Temperature, if only one gauge, then Boost and Water, imo, that's if SPA do that combo, which I am very sure they do.