Performance impact through navigational attributs?

Hi experts,

(this question referes to BEx Analyzer and BEx Web-Analyzer frontends).

I'd like to get some feedback if there's any performance-impact to expect if one provides many navigational attributes in a query - or an InfoProvider.

Let's say we've got a Cube with 5 activated nav-attributes

and a twin-cube with 50 activated nav-attributes

We define the same report on both cubes. The report has none of the nav-attributes in the initial drill-donw, but all of them in the free-characteristics.

Does this it make any difference concerning the performance?

The only downside I'd expect is the fact taht the free-characteristics become quite un-overviewable.

Which brings me to a connected question: Is there any way to define "groups of characteristics"?

E.g. I'd like to provice 30 navigational-attributes for material-attributes (color, type, shape, etc..., etc...).

I wanna have this nav-attributes available in the report - but I do not want to have extremly long lists of attributes (for example in the context-menu "Add to drilldown"). I could imagine the option of having a node "material-attributes" in the list, which can be expanded to find the nav-attributes.

Did you ever face similar problems?

How did you handle them?