This is a NEW accumulator manufactured specifically for the MR2 Spyder with the SMT shifter.  It has the correct pre-charge pressure, and it has been bench tested to confirm that it accepts the same fluid volume as the original Toyota accumulator.  

A failed accumulator will usually generate error code P0942.  You can check your old accumulator by unscrewing it from the HPU and inserting a small screwdriver into the pressure port.  If the screwdriver goes in 1.25 inches, your accumulator has not collapsed and it's likely just fine.   If it goes in further, it indicates the rubber bladder has failed and lost the nitrogen pre-charge pressure.  It is possible that a slowly leaking accumulator will pass the screwdriver test, even though some of the nitrogen pre-charge has been lost.  However if it has a slow leak, it's only a matter of time until its fully deflated.  

You can remove your old accumulator with a rubber strap wrench. Just let the car sit overnight for the system pressure to bleed down.  To be extra cautious you can throw an old towel over the HPU as you unthread it.  If brake fluid dribbles onto the crossmember, just rinse it off with water.  

In the past a Porsche accumulator has been suggested, but it will not work (I tried it!).  The Porsche accumulator threads match, but the precharge pressure is much too high, so it will not accept any fluid from the SMT system.  The SMT system will create a system pressure error code. 

A new o-ring is already installed on these accumulators.