You will find much better performance with the turbo. Nice thing about turbo engines, if you don't put your foot into it, you are running very economically, but when you need it, the power is there. Also, I live in mountainous country and commute daily between 4,700' and 7,000'. A turbo engine doesn't 'know' it is at high altitude because the boost pressure overcomes any reductions in ambient pressure. And when you need to pass that semi going uphill, the turbo is marvelous.

One precaution with a turbo. NEVER 'blip' the engine before turning off the ignition. The turbo will be spinning at high speed with no oil and that is not good. It's always a good practice to let the engine idle briefly before shutting it down. Volvo turbos are very robust and shouldn't give you any problems if treated properly. Absolutely do use synthetic oil (I use Mobil 1) and change no less than every 5,000 miles--turbos are hard on oil.

96 850 Turbo, 86K miles