well on your engine you have 2 small belts instead of one belt like the 104 and 112 engines have. and on your car, those belts are know to crack very easy and stretch so if it were me i would replace the belts again seeing as how it's been 1/2 a year already and since you will have to take them off anyway. just check them first...shine a light and see if the grooves are developing any cracks in them. you use a torx socket to release tension on the belt to remove them (i forgot what size). it's a kinda tight fit down in there but the rachet and torx socket will barely fit!

only replace the shock and the tensioner if they are vibrating/shaking alot or sqeeking. there will always be a small vibration even when new!

Jason