Basic maintenance is great but not really what I was talking about. Making big power out of a relatively small engine means a rigorous maintenance regime and regular tear downs for inspection.
On the gauge question my answer would depend whether the latest simtek has active knock control. The version I'm on doesn't so I have the ability to monitor knock, differential fuel pressure, egt and wideband lambda in addition to boost, oil temp and pressure. It makes for a rather messy dashboard but is essential and has saved my engine by warning of issues on 4 different occasions.