evo mala škola razlika između zender, veloce i Evo kita za 75icu
Both of those bumpers look like UK Veloce items; the Veloce kit was made in the UK by a company that specialised in glassfibre bath tubs(!), called GFM. They also made the fibreglass 33 II bumpers.
The 75 kits were made by "scaling down" an original Evoluzione kit. About the same time that the 75 received its 1989 facelift (red rearlights, white instrument lettering) GFM made a new set of moulds, making the design simpler, and therefore easier to manufacture. All the later components were slightly different to the earlier ones; the rear bumper was less "flat-sided" (ie curved in slightly towards the bottom, more like the standard bumper), the sideskirts were slightly more square-edged and not quite as deep (as well as being noticeably thinner material thickness), and the front bumper was made very slightly narrower, and the central "crossbars" omitted. At this time the front wing extensions fitted to the 3.0 cars were discontinued. So it looks like your black bumper is an early version, and the yellow one a later one. Bear in mind though, that over the years, various people have copied both versions. All the GFM components were designed to fit with the standard factory wheelarch extensions.
The Zender kit fitted to series 1 "Veloce" badged cars was completely different; fibreglaas front and rear bumpers and PU sideskirts. These were designed for cars without wheelarch extensions, though I can remember seeng some "customisations" involving blending GFM front wing extensions into Zender sideskirts (some of the "Lombarda Sport" cars were like this).
