I am currently building an API which will be used by a webservice. 

I was wondering what performance issues I could meet if I built my API using a large amount of **static methods**.

The original idea was to build expert objects which act as services.

In a single user environment this approach was great! 
But I will soon need to port this to a multi/concurrent user environment.

What kind of performance issues might i encounter with this kind of architecture?

Best regards,

**Edit:**

The static methods hold no static variables and have no side effects. They simply execute a normal routine where everything is instantiated. (ie. vars and objects)