To be honest I bought mine because I wanted it, I have no idea if I will sell it but being that I rarely do I somehow doubt it. If it happens to go up in value that would be nice but the pleasure I have already had from the car means it owes me nothing.
In most cases tasteful mods will not detract from a good cars value too much especially if a future owner if they wish can return it back to standard. In the case of 3200's at least numbers remaining will probably be the key factor.
The splitter looks good but each to there own.