Pertronix confusion

[porschetub]

Keen to order Pertronix for my 71 2.2T with marelli dizzy,mine is a S112BX but our host lists for S112AX only, an older thread on here shows this unit (#MR-LS1) fitted to the BX?
I have disembled mine and find it to be in very good condition,the cap and rotor appear to be as new also,besides going to a Bosch unit is expensive and not sure what can be the sense in changing if buying an "unknown" used one.
My take on this is that the 2 serial numbers (BX and AX) indicate differant advance curves perhaps?? I don't have the other to compare with mine but pics indicate they are identical to look at?
Another vendor states the unit fits both with those numbers?, more confusion..........
Advise needed from those who have experience with this conversion,thanks.

[porschetub]

Wow amazing that no one can answer this thread,come on someone must have done this with a Marelli ?,cheers

[porschetub]

went for a punt on this one and ordered module and coil from our host ,already had the earlier Pertronics 1 coil but thought an upgrade to the Pertronix 2 unit so coil will go on the speedster t4 motor with has the earlier unit with german made 009.
I read on the grapevine these units give a handy power increase over the stock ignition ,time will tell.