Re: 156 2.4 JTD Coilover Suspension Set up
You would do better spending 400quid on koni adjustables complete kit rather than non branded/unkown coilovers (if they are)
at least with adjustables you can alter the settings, ie. a bit softer for the wet months.
the offset on 17" rims is 41.5 I think, but they fill the arches completely and are 7" wide as opposed to 6.5" wide on the 16" teledials.
Run 225/45/17 if you are upgrading from 205/55/16, its a closer/best rolling radius match, better match than 215/45/17 that alfa recommends on 7J rims.
A good suspension will only highlight the fact that 16" rims have too much side wall, so you may as well start looking for 17" rims if you intend to sort out the suspension.
Of coarse, spending this amount of money, you may as well put in the Q2 LSD. This £ for £ is probably the best improvement as the LSD can be bought for £230, just the fitting that takes the time.
As for P6000, the first and last time I used these was 11 years ago, they were dire in the wet then and by the sounds just as bad now.
A good idea is to run a set of rims for winter months and a set for dry track days. Conti sport 2 is a good tyres for track/dry general use as it does not have blocks of tread, rather complete rings, so it can with stand a far bit of hammering befor getting too hot - but can sacrifice in the wet - hence the 2 sets of rims idea.
Only probelm with that (as I have found as I have 3 sets, wet/winter 16", intermediate/road use 17" and full on 17" slicks) is that the car looks good on your favourite rim, so you sacrifice drivability for looks - vanity!
The offset on most (if not all) 147/156 17" 7J rims is like paddys, as he says, a great stance, really improves the look of the car.