read the sticky- nobody posts here anymore about mini-z.
go to:
www.mini-zracer.com
and repost.
To answer quickly- yes, that is a t-plate. The stock one is made of plastic. Upgrade ones from Kyosho and other manufacturers are available in different materials. There are variations as well depending on your chassis config. Since you said MR-02 Enzo, that is "MM" or mid-mount. So you would need MM plates.
If your car was handling okay with the stock plastic plate, order the stock replacment part (consult your manual for part number). If you want to tune your car, you can pickup a pack of t-plates (usually hard, med and soft come in a pack). Then try them out. The hardest one gives the most steering response but at the expense of rear end grip. Soft would be opposite.