It is always advisable to have a filter as the last component prior to the IP to prevent any contamination from causing IP damage. If for any reason you cannot install the main heated VO filter just prior to the IP I reccomend installing a "chunk catcher". Using a clear body inline filter similar to the one pictured here also allow you to see if any air leaks in the fuel system are present AND will help you determine how long purging (at idle) takes.
These are usually available from local auto parts stores. They can also be ordered from the component vendors section HERE.