Q: Do these actually help alignment hold, or just handling?

Both, and they are linked. By minimizing unwanted suspension movement, the kit improves alignment retention, so your settings stay put mile after mile instead of drifting as rubber flexes and ages. The handling gain, crisper rear response and better mid-corner stability, comes from that same reduction in deflection. Owners report the upgrade results in better handling and alignment, which tracks with what removing compliance does.