The aluminum is a D4 sub correct? That means you can wire it at 2 or 8ohms. You cannot have a 4ohm final load though.
I know the Ti's handle more then double thier rated power but I havent really heard of anyone doin it to thier Alum. Maybe the Ti is what you shoud look at, or a different driver. I wouldnt feel comfortable sending a sub 200% its rated power unless I wasnt worried about paying for a new one.