Either they know how to do it or not and if they want to charge you through the nose as Merchant said try a Nissan dealer it's a simple 10-15 minute procedure...
From an old write up-
[FONT=Verdana, Helvetica, Arial]This refers to advancing your stock timing. Stock timing on an FX35 is +15 BTDC (as per underneath the hood, driver's side label) and FX45 is +12 BTDC. Timing bump changes this to +17 and +14, respectively. What does this mean? This means that the spark plug will fire EARLIER in the cycle, causing a more complete fuel/air burn since there's more time allowed for the ignite. You'll have some gains from this, but you'll lose 1 mpg (worthy trade-off in my opinion). The down-side is knock/ping. If you do this, you MUST use 91 or 93 octane gas (which you should anyways, the extra 20 cents per gallon only costs you $100-150 extra per year on avg and saves your engine of knock and gives you increased power and fuel economy, which makes up for some of the extra cost you pay). This timing bump must be done by a tool called the "Consult" or a program on a laptop with appropriate OBD-II/USB cable. A Nissan or Infiniti dealer can do this for you, and it is recommended to speak with a tech instead of a manager. If you speak with a tech while getting serviced or at the dealer for any reason for your car, you might be able to get him to do this for free, since it is a 5 minute plug-n-play procedure. Ask that they advance your timing 2 degrees, but make sure they know you want it +14 or +17 total (+12+2=+14 and +15+2=+17), and not +2 or you'll get horrible power loss (honda-civic-style-power).
I didn't have any other work going on so I talked my service manager into doing mine for 50.00. The guy who they first roped into it scratched his head for awhile then another tech came over and hammered it out in....15 minutes.
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