In this post i will gather all the info about which cars you can retrofitting a Q2.
I'll edit my post as soon anyone offer new info on this matter.
If your car use a 95721110 open differentiale then Q2 ( 55208952 ) semi lock will fit to.
This is just a guide ! It is not my or AO (alfaowner.com) responsibility and we are not to blame if don't fit. This is just a guide.

read about it here :
Alfa Q2
ALFA 145
2.0 TD
ALFA 147
M15 1910 JTD CF3 8V 85 KW Ring gear 57/17
M16 1910 JTD CF3 16V 93 KW Ring gear 57/16
M17 1910 JTD 16V CF3 103 KW Ring gear 57/16
M18 1.9 JTD 16V CF3 136BHP DEPOT. BELGIUM Ring gear 57/16
M19 1.9 JTD 16V CF3 150BHP Ring gear 57/16
M87 1910 JTD CF4 8V 115HP DEPOT BELGIUM Ring gear 57/16
M88 1.9 JTD 8V CF4 Ring gear 57/16
M91 1910 JTD CF4 16V 136HP DEPOT BELGIUM Ring gear 57/16
M92 1.9 JTD 16V CF4 Ring gear 57/16
(all JTD except 100 bhp 8V)
GTA 3.2 V6
ALFA 156 (X1 156)
M15 2500 V6 24V Ring gear 63/16
M25 1910 JTD 8V 85KW Ring gear 51/17
M26 1910 JTD 16V CF3 Ring gear 57/16
M27 1.9 JTD 16V CF3 Ring gear 57/16
M29 1910 JTD CF3 136 BHP DEPOT BELGIUM Ring gear 57/16
M30 2400 JTD 10V 110 KW Ring gear 57/17
GTA 3.2 V6
ALFA 164
2.0 V6 Turbo
ALFA 166
2.0 TS
2.0 V6 TB
2.4 JTD 10V
2.5 V6
3.0 V6
3.2 V6
(six speed 166 with petrol engines)
ALFA GT
1.9 JTD
3.2 V6
GTV/Spider
2.0 V6 Turbo
3.0 V6
3.2 V6
ph1 gtv 5 speed
Fiat Stilo
M88 1.9 JTD CF4 8V 120HP 88KW (but only with
Code D10974 Transmission !) Ring gear 57/16
M92 1.9 JTD CF4 16V 150HP 110KW Ring gear 57/16
M30 2.4 20V Ring gear 57/16
Fiat Bravo '07
1.6 JTD
1.9 JTD
More to come !
Tell me what you know for sure ! or ask q here
retrofitting a q2 to an existing alfa (Retrofitting a Q2 to an existing Alfa)
Note: Earlier models have speedo drive on the differential, so may fit but no speedo. All late models (~1997 onwards) have speed driven off the ABS system.
This post if for sure knowlages only.
And thanks for all you guys help for putting this list together