How much for a 'gut rehab' in San Diego?

[Ali Esfandiari]

We are in escrow for a 3000sqft property in San Diego.  I've gotten estimates all over the place.  May duck out of escrow as we have a week left to remove contingencies.  What's a realistic 'retail' cost for a gut rehab (down to the studs, new everything - pipes, electric, windows, roof etc.) with medium-end finishes?  So far I've gotten a 15k quote for architect/engineer, and contractors 'pall-bark estimates' (they cant give firm estimates without a formal plan) from 250 to 500!  Our budget is 300k.

Any Advice?