Of the volvo OE 52MM I've seen (not counting r-sport cluster small gauges):
Ambient temp analog C of F
Ambient temp digital (Toggles C or F, same gauge)
Oil temp (analog only IIRC) C or F
Boost TIC or just T
Oil pressure 3 and 5 bar
Fuel economy
Clock
Small tach
Volts
Just the regular 3-pack and the 2 additional spots would probably be sufficient I'd think for an N/A car. I'd probably rather have ambient temp over oil temp for an N/A car, the oil takes forever to warm up, it's almost most useful just telling you that the oil might not be getting warm enough on short trips on the average N/A volvo. Boring gauge.
If you like gauges, probably big tach, small cloch, regular 3-pack with fuel economy instead of boost, and add an ambient temp gauge? I use the clock a lot and like analog clocks in cars, but most stereos have clocks now, but I don't care about stereos very much and don't like them shining in my face. Would prefer clock to an oil temp.
Forego the oil temp, forget the extra super $$$ 3 pack for the speaker cover?