This is a tortured reply!

There is absolutely NO way to know for sure if you will need a Camber kit for your car without an alignment after you install the springs-PERIOD.

With that said, you can estimate the change in Camber-for each 1" of drop there will be a change of -.84 degrees from the setting you started at. If the car was at -0.2 you will be out of factory spec at -1.4. This is not extreme but tells you that there is reason to consider kits all around the car. A 5th gen Prelude has a factory spec of 0 degrees +/-1 degree for the front (BASE) and a range of +0.3 to -1.8 degrees in the rear. You want a little negative camber and -0.2 to -0.6 or so is fine for a daily driver. Toe settings are also critical to tire life, btw as is rotation. Check on both the Ingalls and SPC sites for excellent articles on this subject.
How low can you go without rubbing depends a lot of tire size and offset. Keep in mind that the lower the offset the closer to the lip you are. A +48 is fine for many setups (stock is +55). How low should you go with a daily driven 5th gen-personally I keep mine at 1.7" up front and 1.5" drop in the rear with the Neuspeed Sport springs. I rarely have trouble with getting over bumps. We did try the lower perch position on the Koni shocks-and had nothing but trouble with the driveway.

Happy holidays