BTW, I re-read the OP and see you are interested in an engine monitor as well. There are lots of options; I have the EI UBG-16 and am satisfied with it. Through next month they're running a rebate to get a fuel flow module, transducer, and extra temp sensor of your choice (I'd recommend oil temp) free when you buy the UBG-16. It won't replace any of your primary engine instruments, but it will monitor CHT/EGT and pretty much any other engine parameters you want, record them, and let you download them to your computer for later analysis. It will also allow you to set alarms for any of those parameters, and flash a big red warning light when one of them is exceeded.
It's $1215 from Gulf Coast Avionics, including CHT and EGT probes for 4 cylinders. Installation labor will, of course, be quite a bit more than for the tach, but an engine monitor is a really good idea.