Caliper Critical Dimensions
&
Caliper Size Selection Notes

Mounting:
In order for the front calipers to fit, your car must use the later ATE calipers and mount on spindles that use a 3.5” (89mm) bolt spacing (center to center).  Typically, 1750, 2.0L 105/115 cars, and 101 Giulias (w/ Dunlop/Girling calipers) use this bolt spacing and are a direct bolt up.  Earlier (1600) 105 cars w/ ATE and some Juniors used 3” bolt spacing, and the calipers will not match these cars.  The best way to mount the big calipers on these 3” cars is to swap in spindles from a later car.  This is a simple and direct bolt in replacement. Please contact us with any questions you may have about this installation.
The rear caliper bolt spacing is constant across all models and years.  The rear caliper kit will fit all of these cars.

Wheels:
Wheel clearance can be an issue as well.  Stock 14" x 5.5" wheels will probably rub along the top edge of the caliper.  The Turbina style will rub for sure.   It is a close thing, easily solved with a small wheel spacer.  Other stock alloy offerings - no data to this point.  Any 14" x 6" wheel will most likely fit.  For instance Panasport 14"x 6" fit fine.  15" wheels should be completely clear - by a lot. 
Please contact us with specific wheel questions.

Master Cylinders:
For suspended pedal cars, the stock 20mm master cylinder is a workable solution for the smaller versions of the 2800 calipers.  Moving to the 22mm size master will accomodate up to 1.62 fronts and the 1000 rears.  For cars using the 1.75" fronts and the 1000 rears, or for those who just prefer a hard pedal, the 23mm master cylinder is a better choice. 
Cars with floor mounted pedals have master cylinder limitations that may dictate maximum caliper piston sizes.
Please contact us.

  Brake Bias: 
For any brake system, all other facets remaining constant, the force, or grip, applied by the calipers is directly proportional to the caliper piston area.  The balance of the forces applied front and rear, is basically a function of the ratio of front piston area to rear piston area.  The fronts with 1.375" pistons gives a piston area almost identical to the stock ATE calipers.  For this model, used with the stock rear ATE calipers, the original brake bias will be undisturbed.  The 1.62" calipers have a piston area that is more than 70% greater than the stock ATE.  It is safe to say that with this configuration, the term brake balance no longer applies!  The 1.75" version is the same only worse!  In both these cases, an adjustable brake bias valve is pretty much mandatory. 

Interestingly, with the 1.62 fronts, the addition of the big rear calipers gives a F/R piston area ratio almost identical to the original, and brings the brake balance back almost exactly to stock!  This configuration gives almost 2X the original braking force - without upsetting the car, gives great modulation, larger front pads for better pad wear and local thermal management, and the light calipers give waay better unsprung weight for better handling and road holding.  It is a pretty sweet combination, even if I do say so myself!  This is by far our strongest recommendation for a proper brake upgrade.
The use of the 1.75" piston calipers, even with the rears -  best with an adjustable bias valve.
Actually - once you start monkeying around with the brake bias, and perhaps move weight around in the car (and take it out) the original brake balance is likely to be lost anyway so planning on using an adjustable bias valve is not a bad idea.   

Brake Boosters:
Questions about brake boosters come up all the time.  To be honest, I do not think there is a simple answer to this question.
Everyone seems to have their own idea of what is acceptable - or desirable.  Adding a larger caliper will make the pedal more "sensitive" and probably harder to modulate.  Boosters make this situation even more sensitive.  Some drivers are able to deal with it.  Some prefer to eliminate the booster entirely.  My recommendation would be to try it (carefully) with the booster, then try driving with the booster disconnected to see if you like that better.
From my personal experience - a stripped out Super with a 2.0L engine, 1.625" fronts, big rears, 22mm master cylinder & booster - the brakes are phenomenal and work without any noticeable differences except for the fierce stopping power.  There is no thinking involved - just hammer the brakes as usual.  For me, this is an ideal combination of hardware.