Only the seller can answer how much s/he is willing to come down on price, if s/he is serious about selling. The market, ultimately, dictates what a home is worth.
I must agree with Denise that the pricing also depends upon the condition of the home and the model. Has the home been updated with a new kitchen and appliances, floors, windows and or HVAC? Is the home freshly painted? These things matter. Regency townhomes are among the most upscale in the Quailbrook area. Some include basements as well as garages. The price might be high or right on target. Only months ago, another Quailbrook home sold for $335,000.
If you are not already working with a REALTOR, I would be happy to provide you with a comparative market analysis or CMA. If you are working with a REALTOR, ask him/her to provide one for you.
I don't know where you found assumptions of a 15% decline in local market values. There is a saying that all real estate is local. It's true. The New Jersey Association of Realtors (NJAR) has produced "Get The Real Story" on NJ real estate that's available online at: http://www.realstorynj.com
I also provide regular monthly stats on our local real estate market on my Blog, Somerset 08873. Talk with your REALTOR about your concerns. And, again, if you are not working with a real estate agent, I would be happy to assist you in your search for a Somerset home.
Best of luck to you,