I have had 2x 94 rev3 turbos so maybe not the same shocks as the rev1 na but the following might give you some idea how long shocks last on these cars.
On one car the original toyota shocks lasted 9 years and did 60,000 miles when one side started leaking and failed mot.
The replacement fronts did 60,000 miles and 98,000 miles
(replaced in pairs).
The replacement rears did 100,000 miles.
On the other car the original toyota shocks lasted 18 yrs and did 83,000 miles.
They were not leaking but the handling was not as good as it should be
(the previous owner didnt drive it much as the ride was too harsh, but I found that even though it had passed an mot, it wouldnt hold the line I was expecting when cornering which meant had to delay getting back on the power, making it much slower than my other mr2).
On removal one of them was very slow to rebound.
How long your shocks last depends how bad the roads are in your area.
Obviously roads with potholes, speed bumps or generally poor quality bumpy roads will wear the shocks out quicker.
If you can, try and get a ride on a twisty country road in an mr2 that has recently had the shocks done.
You will know straight away what to do with your shocks.
I would not lower a car if going anywhere near multi-story car parks as some of the angle changes on the ramps are too steep for non-lowered cars and the nose cone gets grounded.
Same happens when I visit my Dad, just on the slope of the approach road to his garage
(unless I do it in reverse).
Good luck with the car.
