You could be right about the wishbones being the same David, but my main point is that Autodelta were not happy with the long term performance of the Powerflex bushes they were using for GTAs.
The problem was specifically to do with the front wishbones, from memory of a conversation with Jano about this the problem was something to do with them being ever so slightly too big.
I didn't ask if this problem occurred for other variants of 156's, 147's as far as I know their website only offers the wishbone upgrade for GTAs.
..but then again their Website isn't always 100% up to date with everything they stock.
Originally Posted by David C
The GTAs use the same wishbones as all other 156, 147 & GT.
BTW my reference for the fact I thought the wishbones were different was this quote from an early review of the GTA where when listing the differences from standard 156 suspension it referred to unique suspension arms for the GTA, I thought this would cover wishbones.
Originally Posted by Car Buyers Guide Review
The suspension is a derivative of the tried and trusted high double wishbone at the front and MacPherson strut layout at the rear used in the ‘regular’ 156. A new front suspension was designed specifically for the GTA. Unique to the GTA is a reinforced lower beam, a special wheel strut with a different steering link fastening position, lower ride (and I mean low), new shock absorber and spring settings and a bigger diameter roll bar. This improves the already superb double wishbone suspension. Tyre grip is outstanding as external lift is counterbalanced by a recovery of camber. There is little or no diving under braking and there is virtually no lift even under hard acceleration.
At the rear, the suspension is a MacPherson configuration, with the GTA in particular featuring a different body attachment position; special spring setting; different shock absorber and bush stiffness and an anti-roll bar with a bigger diameter.
Other features include an upper end bump-stop in Cellasto (closed-cell polyurethane that maintains its flexible properties over time); an anti-roll bar connected directly to the dampers via connecting rods made out of structural plastic and jointed to steel ball joints; and pressurised double-acting hydraulic shock absorbers in high strength steel of reduced thickness. Lastly, suspension arms are all unique to the Alfa 156 GTA.
The GTA’s roll stiffness is increased with a 20% stiffer front anti-roll bar and 28% stiffer rear bar. These modifications allied to the spring changes gives a total increase of 30% front and 40% rear. The ground clearance is reduced by 20 mm.