The MR2 has struts at all four corners, and front and rear sway bars. In 1993, the suspension geometry for the rear was altered to reduce toe out change under compression. In turned out that the 91/92 cars had a tendency to oversteer under aggressive driving conditions, which wasn’t good for publicity. As a result of these changes the 93 and later MR2s tend to understeer. For many racers, the 91/92 suspension is preferred, although it seems to be more driver preference than anything else.
Numerous suspension changes were made to the 93+ cars, including revised pivot points for the rear tie rods and lower control arms, lower and stiffer springs, and a different sway bar. Both the tie rod and lower control arm pivot points were moved inward to the center of the car, reducing the amount of rear toe change to the car. The front sway bar endlinks were strengthened in 93, as the earlier design was susceptible to breaking in the earlier cars. Caster is apparently not adjustable in the ’93 models, but is in the 91/92 cars and possibly the 94/95 models.
For 91/92 owners, lowering springs are a common upgrade. The spring rates for the ’91/’92 models are 130 lb./in (front) and 209 lb./in (rear).
H&R springs are widely used, as well as Eibach Sport springs. The TRD springs are actually Eibach-made, so you might want to save yourself the extra money and just buy the Eibachs. Lowering springs should not be used with old stock shocks, as handling may be adversely affected. Springs typically run about $230 new.
Many MR2 owners upgrade to Tokico adjustable shocks, although many owners like Koni adjustable shocks. AGX and SPAX are also available. Adjustable shocks are a great way to tune your suspension to your preferences, and are especially important for road racing and auto-x. Shocks typically range from $100 to $140 per shock.
The problem with adjustable shocks and stiffer, lower springs is the lack of height adjustability. If ride-height is important to you, you may want to upgrade with TRD, Toda, or Tein coil-over shocks. These units include adjustable shocks, heavy-duty springs, and a threaded spring perch to set ride height with. These units are expensive, ranging from $1400 to $2500.
Aftermarket sway bars are a good way to flatten the cornering of your MR2. The downside to oversize sway bars is that they will also stiffen your ride as they positively connect opposite sides together, and will probably not tolerate roughs roads as well. Oversize front and rear sway bars are available from TRD and Suspension Techniques.