I'm surprised you haven't been able to reach Keith. Have you tried calling him?
Some parts from the 300ZX do fit on a Q45. Some members have used some performance parts for the 300ZX on their Q.
You'll want to check pricing at I.O.S. (Infiniti of Scottsdale):
http://www.infinitipartsusa.com/partloc ... &year=2007
FRONT DUST BOOTS (Active Suspension)
Part Number:
55242-67U00
I.O.S. Price: $27.12 each
REAR DUST BOOTS (Active Suspension)
Part Number:
54055-67U00
I.O.S. Price: $22.12 each
Fluid A - Active Suspension Fluid (Genuine Nissan)
Part Number:
E2901-62U01
I.O.S. Price: $11.25 (1 liter)
I don't know if these are what you asking about
BUMPER ASSY - BOUND FRONT (Active Suspension)
Part Number:
54050-62U20
I.O.S. Price: $22.20 each
BUMPER ASSY - BOUND REAR SUSPENSION (Active Suspension)
Part Number:
55240-62U20
I.O.S. Price: $41.02 each
1. How much fluid are you losing, from where and how often?
2. How many of your actuators are leaking and which ones?