From Good-win Racing's Website
"KOYO 55mm R2277 Aluminum High Performance Miata Radiator:
All aluminum construction, polished tanks, affordable, and effective. With a 2 and 1/16th inch thick core (55mm) you will never again have cooling problems. This miata radiator is THREE times thicker than a stock miata radiator on 99-05 cars..."

This is from my old '99 M62 supercharged car. This rad was used for about 2 years until I sold off the boost. Its been sitting in a storage box for over 4 years now. Worked well with TDR Intercooler kit when I last used it. If using it in a naturally aspirated NA you might need to do some adjustments in the stock position because this is a massive radiator (3x as thick as an OEM). I've only had it in a SC car so I can't comment on how it fits in the stock mounting position. When I took it out it didn't have any leaks in the tank or core but the cap/neck might need to be looked over as it had the tendance to slightly leak at times - not seriously but it needs to be looked at. Shuhart @ TDR fixed this on other KOYOS with some JB Weld on the inside of the neck where the cap is welded to the neck.

New @ Good-win Racing: $448. Link
For sale as is: $175 or best reasonable offer
Its a good TCB rad for any NB force induction Miata owner on a budget.