OK, I need a ruling here.
Pg 218 states you can upgrade a Comm Unit to a computer by paying 110% of the computers price. So if I'm reading that right I can upgrade a Comm Unit to a Tier II computer for $275 ($250 + 10%). Since my Custom Rig is considered a Comm Unit, I can upgrade it to a Tier II computer for the same cost.
Comm Units are considered a Tier-0 computer for size. If I upgrade to a Tier II computer the bulk increases, so if I take two levels of Miniaturization I can shrink it back down to a Tier-0 size. (20% of $250 = $50).
So to have my Custom Rig as a Tier II computer implanted with a DataJack it would cost the following:
DataJack (Standard) $625
Tier II Computer Mod $325
- $275 for the upgrade
- $50 for the miniaturization
Range II Mod $50
Artificial Personality Mod $25
Total: $1025 Credits
This gives me a DataJack, Comm Unit, Tier II Computer w/ Artificial Personality, and Custom Rig all in my head.