There is a set of late alloy calipers on The Samba for $1K
Keep in mind there are early (pre 74 I think) and late alloy calipers.
There is a visual difference. the early ones have more material removed form the casting possibly adding to the flex? Later ones have more material, Stiffer?
Back in the day many removed them to go to bigger SC calipers as the hot ticket.
I like the low weight of the alloy calipers, they seem to have come back into popularity among the early 911 crowd.
The factory 914-6 GT cars ran the early "S" alloy calipers.
They are 3 1/2" strut spacing requiring you to change the 914 3" spacing struts.
Eric's web site shows and explains all...
Plan on spending almost a grand when all is said and done, they tend to cost $450.00 for cores and another 450 or so to have them rebuilt...( I just did this)
Stoddard has some NOS in stock, I think they were around $2500.00 ?