that striping is a lock to hold the window in so the seal doesn't flex and the window fall out, the installer may not know this if they have only worked on modern cars.
with electroplating the cheapest isn't always the best, electroplating is very labor intensive buffing , polishing. If done properly there are 3 layers first copper then nickel lastly chrome, if rushed the product will be of poor quality.
That sill panel would be deemed structural damage and defect-able .Unfortunately fitting a new or s/h seal panel would cost more than the value of the car
do a depth test with plugs installed from top of plug to the tappet cover see if plug no 1 is sitting in further.
or Unfortunately it may be time to strip down and get to the bottom of the problem
Your car most likely has a auto diff in it, The auto Transmission has a speedo drive gear suited to a auto Diff ratio. motor size gearbox type is irrelevant, tail-shaft spinning speed is what is measured.
the Tyres size will also affect the speedo reading. there should be a tyre specification on the inside of the boot.
If you are considering buying the rubbers off ebay form Our Taiwanese Friends maybe ask a few People about the quality first, I know the taillights fade badly
Most times the seals can actually be reused,
you could also Try, spectrum rubber for a quote,
http://www.spectrumrubber.com.au/index.html
218.741 Screen seal - front - coupe KE35 (takes chrome strip)