WOW, The angles look really out on the OP 4-wheel alignment report!
I've had two V6 Spiders, the 1st from new in 2001, I did 140k miles in less than 7 years. Because of wear on the inner edge of front tyres, I rarely got more than 14k miles. The rears also wore on the inner edge, but not so severe.
I always had a 2-wheel or a 4-wheel alignment at every tyre change, but that did not seem to make much difference and various garages seem to produce conflicting measurements, so I got disillusioned with wasting at least £40 a time. The camber on rear right was always just out of spec i.e. just more than specified by Alfa - they always said that there was no adjustment for camber on the rears.
When I purchased my 2nd V6 Spider in early 2010, it was 8 years old & only 43k on the clock. After running it for for 5 months over 12k miles, all 4 tyres were well worn out and all worn heavily on the inner edge (During that time, I did swap the best tyres from spider 1 to the front of spider 2 to get 12k miles! - Spider 1 had been (and still is) in my garage for two years with a cracked head - another story)
Given the uneven tyre wear and the fact that a number of bushes were shot on spider 2, I decided to get a local Indi garage to replace the front wishbones, all the front and rear bushes with powerflex (except the rear "rose" type bushes on the rear, which were replaced with OE-type bushes), I also sourced OE 4 shocks and springs and in addition new rear ball joints.
This all went well until the 4 wheel alignment, when the rear camber was seen to be 3.5 and 4 degrees for left and right
- much worse than spider 1 and much worse compared to when we started - these numbers are well over spec and the rear looked like this /---\
The Indi got both spiders on ramps to compare measurements, even taking and measuring the ball joints and swapping from spider 1 and fitting to spider 2, but could not come to a conclusion of why the camber was more than 2 degrees out
I did not want to take the risk that another new set of (expensive) tyres wear out prematurely, so without any evidence, I took the decision to "slot" the rear ball joints to pull the camber back to normal (the Indi also added extra nut & bolt to make sure no slips)
Now the rear camber on both sides is and toe in etc was well within tolerances - I suggested that I would like the toe to be nearer zero - so this was set at about 0.5 degrees (I think)
The result was that the car's handling is realy great
, just like a "new car" and, after 15k spirited miles, I have still got 3mm left on the front tyres and 5mm on the rears, all more importantly, all four tyres have worn evenly (subsequently I've had new 17" wheels & tyres fitted
I'm not sure why, when replacing all the suspension bushes etc, the car had excessive camber (or even if that would have resulted in uneven tyre wear
I think the real moral of this story is, if the car is set up within (manufacturer) tolerances, then the car will perform better (in this case by producing even tyre wear)
Could the problem have been caused by some nuance with the V6 suspension? (we know that the the V6 has a wider rear track than the TS - according my Spider/ GTV brochures and those recently published on this forum) - could it be that after replacing with parts with genric Spider/ GTV parts, that these are not right for the V6? i.e. puts the camber Out? - Discuss????
Going back to the OP, I suggest that you check for worn bushes etc and replace those and then get the alignment adjusted so that the angles are within tolerances.
Ignore the excessive camber, and run the car for few thousand miles to see if the performance is impaired and/or the tyres wear unevenly - then its up to you if you want the expense of new bushes/ shocks/ springs etc all round and/or other mods! - good luck