Hi and Welcome.
If you can afford go for the later model, 04 and above will give you maximum benefit, here's an idea of how the car as developed and you will see 04 has the best up-grade (this was borrowed from another site)
I hope this helps
2000 - Mk3 is launched in Europe, having previously been launched in Japanese and US markets. A small modification is made after the car has been rolling off the lines for a while, when Toyota add very small aerodynamic "spoilers" under the car ahead of each wheel. These were fitted to aid high speed stability.
2001 - As 2000.
2002 - Addition of improved Oil Control Rings fitted to the Pistons.
2003 - (Production actually from late 2002) Mid term revision. Essentially a cosmetic overhaul of the car, however some mechanical changes have been made:
New front bumper with integrated front fog lamps.
New headlights with seperate high/low beam units and chrome housings.
New redesigned taillight lenses.
Addition of new colour coded rear bumper inserts adjacent to number plate.
New colour coded side vents.
Interior gets new chrome detailing on vents, tweeter surrounds, heater controls, and door handles.
Redesigned seats fitted.
Instrument and ventilation control fascia's redesigned with new typeface.
New Toyota Branded CD/tuner replaces Double DIN Sony CD/Tape/tuner fitted to previous years.
16" rear wheels replace 15" wheels previously fitted. Rear tyre goes up to 215/45/16 to fit the new larger wheels, up from the previous 205/50/15 sizes fitted in previous years. Front tyres remain the same.
Updated suspension spring and damper setings.
Improved suspension member brace set up installed on front and rear suspension.
6 Speed gearbox fitted to both manual and SMT cars, replacing the 5 speed unit fitted to previous models.
SMT gets Electronic Traction and Stability Control.
Options list is expanded to include TTE accesories, which were previously unavailable in the UK.
2004 - Visually the same as the 2003 car but some major upgrades have been made under the skin. Essentially these have been made to improve safety although they do have the advantage of increasing chassis stifness as well:
New front under-members and momentum cancellers on the strut towers to help prevent the side members from rising in the event of a frontal impact, reducing dash panel intrusion into the cabin space.
Improved in-cabin passive safety package adopting an anti-intrusion mechanism on the brake pedal and cushioning material below the accelerator pedal – where the driver’s heel rests.
Reinforcements to the upper front members and the door beltlines help disperse collision energy forces applied to the front side members, minimising any cabin deformation.
New rear bumper brace, a new strut bracket brace and new floor-to-rocker brace panels attached to the main rear-cabin cross member.
Refinements to the kick panel reinforcements, floor-tunnel reinforcements and floor cross members help minimise intrusion of the dash panel in the event of a collision.
The centre pillar has been reinforced with additional gussets and reinforcement of the centre floor cross-member.
New pads in the doors and retuning the hardness of the trim padding to reduce the chance of crash impact injury to the torso area.
New Steering braces.
New suspension settings.
New design of heatshield fitted to Main Cat to revent the broken weld related rattle on the previous design.
Manifold Support Brackets are now cast steel items, bolted to four points on the engine block, replacing the previous pressed steel items that bolted at only 2 points.
2005 - No technical revisions occur, small small additions to available options packs:
Heated Seats offered as dealer fit option.
"Chrome Pack" option introduced
MR2 Withdrawn from US market
2006 - No technical revisions occur, MR2 Withdrawn from sale in UK and Europe.
TTE (Toyota Team Europe) Turbo kit becomes available for retrofit to all mk3 MR2's.
TF300 run-out model introduced, a "special edition" of 300 cars with various minor cosmetic mods, built to dispose of Toyota GB's remaining stock.
2007 - Toyota cease production of Mk3 MR2 in Japan.