My first IWC was a Porsche Design Titan automatic chronograph reference 3700.
I bought it as a used watch in 1989 SIGHT UNSEEN! When it arrived, I was
disappointed that it didn't resemble the traditional chronographs of the early
60's that I had been collecting. I sold it a year later.
Fast forward twenty years to 2010. I recalled the Titan and decided I would
appreciate the design. It quickly became my favorite watch, and I became
obsessed with the model. I now have three, including two of the first series
that were sold in April 1981 and one of the latest ones (with a caliber 7922)
from 1996. All totaled, I have personally owned ten different Titan watches. I
consider myself an expert on the model, even if some of the history is based
on my best guesses.
Which brings me to a question for @hansgoerter: If your first IWC was a
Porsche Design Titan Chrono, then you bought it in 1981 or later. If you
bought the watch in Zurich in 1975, it is not an IWC but rather an Orfina. As
a person obsessed with the IWC PD Titan, I am happy to be mistaken if the
evidence supports it!