Dunno what you mean about getting 18 size tires with 17" wheels....
Anyhow, as far as learning, you can learn about the basics of engine mechanics and what goes into performance from reading books or car magazines. A book will give you the gist quickly, mags will take a while to compound but will go more into detail on specific products and companies, unlike a book. You can also pick up a good amount of knowledge just from talking to people who know a thing or two about it.....that's where HS comes in handy.
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