I couldn't say, I've never ran my td04 with a filter always had mesh over the intake. I would of thought you would be better on power as its a direct intake
Cut up an air filter and use the mesh from around the outside of it and then use a been tin to shape it, then jubilee it on. done mine like that and it sounds EPIC on spool up
This mite help guys http://www.ebay.co.uk/itm/BRAKE-PIPE-3-16-COPPER-X1-25FT-SOFT-20-UNIONS-10-EA-METRIC-MALE-FEMALE-/290664732412?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item43acf7d6fc