First you have to determine which boat you are talking about there are several different Outbacks and Mobiuss from then with different hulls and ballast configs. Here is the explanation I got from Moomba:

hen it comes to Outbacks, Outback LS, and Mobius Direct Drives there have only been 3 hulls since they were first introduced. I will refer to them as OB1, OB2, and OB3. OB1 was designed for 1997. OB2 was designed for 2001. And OB3 was designed for 2003. Here is the matrix you guys are looking for...

OB1 97-02 Outback, 99-00 Outback LS, 98-00 Mobius (LS)
OB2 01-04 Outback LS, 01-04 Mobius (LS), 02-04 Outback LSV/Mob LSV
OB3 03-04 Outback

The Mobius V and Kamberra had it's own hull from 00-03.

The Mobius XLV has it's own hull new this year.

Hope that explains it.

I have a '01 Outback - they didnt have a built in ballast and are kinda more ski-oriented. But if you weight it it will throw a pretty good sized and real good shaped wake