A lot depends on what you are doing and what car/motor you have I guess. Having the pump inside of the tank does help to quiet things down quite a bit but as you noted it does cost a lot for the set up. These are some tips that I have picked up for what is is worth.
If you are going with a trunk mounted cell, I recommend that you go with an aluminum one with a sump. You can either notch out the trunk floor for the sump to protrude out of the bottom and flush mount the cell in the trunk or mount the cell on 2" supports inside the trunk to give the sump clearance. What ever brand of pump you go with make sure the intake to the pump is below the bottom of the cell - ideally even below the sump bottom. Install an 80 to 100 micron screen filter on the pump inlet side and I would recommend installing a shut off valve unless you get a filter that has one built in. This makes it much easier to clean you filter with out draining the cell and making a mess. Install a tighter filter on the outlet of the pump - at least a 40 micron screen or even tighter filter of some sort. Again depending on what you are going for with your car, if you need to run a fuel line the SS braided lines are generally easier than hard tubing. The cell vent can be as simple as a line off the top of the cell venting outside of the trunk. You can also install a roll over check valve in the line (for obvious reasons) or make a loop in the tubing before it goes out of the trunk. Depending on the pump you use you may need to run a return line from the regulator back (a regulator designed for a return line). Some pumps have internal bypasses and don't need a return line. There are other factors to consider too, such as proper sizing of your pump and lines for the application. The pump suppliers can help with that depending on your motor Hp. Be careful not to oversize your pump like many people do. If you have a no return line set up and over size the pump it will get hot when you are not using a lot of fuel. Conversely if you have a return line and an oversized pump, you can be pumping a lot of fuel back into the tank at high volume when you are not using much and making it foam up inside the tank.
