Join Date: Nov 2001
Location: state of confusion
Actually, when it comes to handling balance - they can have a LOT to do with each other in this situation where you have a PHB in combination with the OE triangulated 4-link. It will define how stiff (soft, actually) of a bar you can run . . . if you end up running a rear bar at all. Unlike with the S197 and its 3-link + PHB arrangement, details like LCA and (particularly) UCA bushing stiffness, PHB bushing stiffness, and PHB height matter a whole lot.
You have to consider how these components interact with each other in the full 3-D geometric sense. Technically, a tri-4-link plus PHB is overconstrained, meaning that something has to give or else the suspension won't move without offering resistance that can behave very much like adding a huge drag racing "anti-roll bar" along with the relatively soft OE rear bar and trying to take corners at least 'briskly'.
While it may be possible to come up with an overall configuration that feels more linear over most of the range, it will have a built-in tendency for abrupt changes in behavior around peak cornering as the competing definitions of geometric roll center heights move away from each other vertically because of suspension bump or rebound travel.
Mine: '08 GT, 5MT, black/light graphite, un-Fstock (DD, occasional track day)
Wife's: '10 Legacy 2.5GT (DD, six-speed manual)
Spare:'01 20AE Maxima, 5MT (also my bad weather alternate)
Various Loose Parts: '79 Malibu