SQL Syntax Performance Tuning advice - dates

Are there any DONT DO for SQL and dates when it comes to performance

Specifically i'm trying to optimise this
If i pass in a @TwoDaysBeforeDate as '2014-3-19'
is this the best way, or should i use something like getDate(-2) for performance ?

select * from vwQuickAlertMaster where vDeviceName != '' and dDeviceLoggedDate >= @TwoDaysBeforeDate and bIsacknowledged = 0 and iSoftwarePriority = 3 and bIsAlert = 1 order by dDeviceLoggedDate desc		  

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thanks