Had a day and a half away from the 'puter so i think its time to add my experience / thoughts.......
Springs are rated at whatever poundage / inch of travel irrespective at what state of compression they are in as long as they don't become fully compressed they will always react the same. So, 14" dampers with 9" springs will react the same as 13" dampers + 1" extension with 8" springs just with the 14" dampers you will have more travel. The length of the springs governs the ride height of the car thus screwing the ring nut up and down the damper adjusts the ride height of the car / corner weighting rather than adjusting the handling. Cheaper, 14" springs, will be fine with the correct length, 9", springs on.
From my own cars on the road the rear of the car is ideal with 14" damper + 8 /9" springs, whether 13" + 1" (8" spring) or 14" (9" spring), allowing plenty of adjustment for ride height. Car runs well on 4" front and 4 1/2" rear allowing enough clearance for most speed bumps. The front, however, with 13" + 1" with an 8" spring is at it's lowest setting for the front ride height at 4". Obviously when it comes to track time i would ideally like to lower the car as much as possible so next time i'm going for a 14" damper (for longer travel) with an 7 / 8" spring to give the lower ride height when required. The rear there is plenty of adjustment available.
Ideally, for the cost of springs, i think i'll go for a stiffer track set of springs and also the standard road going springs (350 front and 250 rear). They are easy to change and would make a big difference on the track.
Just my thoughts.....Andrew