Most of the turbo timers are easy to install. It involves plugging in a harness and splicing a few wires. Generally, though, the extra features aren't really worth it. Get a turbo timer to have a turbo timer. Get a boost gauge to keep track of boost.
I have the HKS type-0 and I'm pleased with it. It does what I need it to do. It comes with a voltmeter that I never use.