recomended data type for time members keys

Hi all

I am used to using integers as member keys in time levels.

For example the key for 2012-01-01 would be 20120101 and it's name in date format would come from another date or string column.

It forms no problems later when deffining this dimension's type as time (same goes with its attributes,

allowing the use of time related functionality in cube using this dimension).

Shoud this change or hinder process or query perforemance once members keys are changed from

integer to date data type?

This will allow implementation of time functions in excel over these attributes which is not possible as long as keys are integers.

TIA Rea