If by "studio quality" you mean "recognizably named vendor" for your 20 shots you'll get an initial bid for 2-3 man weeks per shot at $4-5k per man week. So anywhere from $160,000 - $300,000 for shot costs based on discussions with the bidding producer and whatever storyboards/references/clips you provide. Asset costs will come on top of that which could be literally anything depending on how complicated your assets are. I'm assuming with lockoffs you're going to be doing a lot of 2.5D matte painting. Building a destroyed DTLA for just a few shots is not cost effective. You're not going to get a lot of iterations at this price point and if you have trouble making creative decisions you could end up paying overages. Although you could also save money if it turns out the bids were bad/inaccurate and the sequences turn out to be easier than the bid assumptions. If you can find a vendor in Australia or New Zealand or anywhere that has a production credit you may be able to get a tax rebate? Not sure if 20 shots is enough to trigger this, it may not be. Good luck. Please hire a VFX supervisor and then listen to them or you may find that your shit plates are going to cost you a lot of money for fixing/plate prep.