Did you already buy it? The 1987 Model has a different electrical setup and the CDI's are prone to fail. They can be costly and hard to find.
You can get a Clarke tank replacement, it is bigger than stock, cheaper than a new metal one. Justgastanks was offering a discount not to long ago to forum members, not sure if it is still going on.
I would start your parts search here. You should get a good Idea how much $ your looking at. Shopping around you may find parts cheaper or better shipping deals.
A forum member works at Procycle and set up a TW page with a lot a parts too.