Tim,
'79 bumpers are the 5 mph chrome railroad ties common with period. The GTI that I now have was factory with the al-u-min-ium bumpers. A plain wrapper '84 Rabbit has the railroad ties on it (figures), so I will have to find them if I go ITC. I haven't heard any pro's or con's regarding the 1.7L and whether it is worth building. The 1.6L in my '79 really brought the car to life last year when I put it in, which is why I hate the idea of getting rid of it. The downside to the '79 car is the fact that there are some flex issues with the chassis, and the dwindling ITC fields.