The rubber boot is what keeps the exhaust smell out of the cockpit. The vinyl shift cover isn't sufficient to do the job. Most of the ones I find are anywhere between torn and out right destroyed. The spider I just parted had a perfect one. In fact, for a rusted out junk, most of the rubber pieces were pristine. It had a new alternator, stainless exhaust, clutch and brake masters, and lots of other goodies that are usually broken on a parts cars.