The Chassisworks g-Link system will allow you to lower the car about 2-3 inches. For moderate to high-horsepower cars it's a great option. More adjustment for ride height and geometry changes, spherical pivots are stronger than the rubber or polyurethane bushed style arms but quieter than a traditional rod-end. You can read more about all the options here:
http://www.cachassisworks.com/Attach...ogs/BG_400.pdf
We typically don't recommend trying to shove a 345 in a mini-tub car. We don't find it to be practical for regular driving. You could probably do it on a show car, but not something that will see any sort of aggressive driving.
The '69 below is running our front and rear suspension systems. It has 18x11 wheels wrapped in a 325/30-18 tire. It belongs to forum member Mark Deutsch.
Remember that while the taller 20" tire will extend further toward the fender lip, it's also going to push the car's rocker further off the ground.