Depending on what you mean by "clanking", could be a failed chain tensioner. They are oil-fed, but have a spring also to prevent catastrophic engine damage if they fail. If your mechanic is familiar w/ 911's, he should recognize source of noise immediately. If not, bring it to a real Porsche specialist, it will be cheaper and less agravating. In all areas of life, use specialists whenever possible. When your ass hurts, you don't go to an ear/nose/throat guy.
If car really does have 29k actual miles, all systems should be like new. Other than seals drying out, nothing wears while sitting. DO NOT start blindly throwing $ at it, replacing random components unnecessarily as recomended above. The Bilstein shocks on my car,(20yrs. and 115k mi.), are like new. They last forever and are expensive. You will need $ for things the car actually needs. Good luck.
