Space saver spare..., can you replace the tire??? Options

[BKLA]

O.K. - I am a complete idiot and I don't know anything about porsche space saver spares.

I bought a used one recently from a PCA member to have as a spare in my 15 x 8 shod 914 6 conversion. its red and clean and nice....but how do these things work? do you put air in them via a compressor or pump and do they expand? if so, how does the tire expand its diameter without ripping? Am I missing something? does the tire just bolt on "as is" and get me to a place to repair or replace the original?

Seems mighty low to the ground and the "aspect ratio" is only about an inch beyond the rim. If I need to put air in it to use it, is the tire replaceable without buying a new, complete spare assembly? (I tried to put air in an all I hear is a leak of some kind.)

I bought it so that I could have enough space to put in a GT oil cooler in the front and still have enough space for front trunk usage. I know I know... I should put a full size in the rear trunk like the GT's had, but its nice to have both trunks....

Any clarifications would be nice!