I don't think going up in MERV would be an issue. I have used a filter house in the past. Both OEM and aftermarket available. Expect to pay more for the higher MERV. Any specific reason going to MERV 11. Link below.

IMO

Here is a link that might be useful: Filters-Now

There is no down side if cost isn't a factor. 8 cleans well enough to protect coils and 11 will also protect those with sensitive lungs.

Thanks for the quick replies. In response to questions:

-I want to increase the MERV to increase the filtration in hopes of cutting down the dust/dander/allergens that gets circulated in the house in hopes of cutting allergies through the winter/spring. I just wasn't sure what the potential pressure drop would be from 8 to 11 and if the system could handle it, but I think that has been sufficiently addressed.

-I should have been more specific in my filter question. Thanks for the link. Would you go with an OEM filter or something like the True Blue from HD or an aftermarket at the filter site you posted?

Thanks again,
/j

I have Trane Perfect Fit cabinet. I have used both OEM and aftermarket. See no difference with the aftermarket. As far as HD brand, I see nothing wrong there. Just make certain you measure for the actual size of OEM, not the nominal size of 20 x 20 x 5.

IMO

Many thanks for helping to inform my decision and save me money. Take care,
/j