If you want a turbo with the exact same fit, boost and power then get the same T3!

If you don't mind adapting the exhaust flange to fit then Mamba have a GT2860R with T3 flange. It's actually be capable of much more power than a stock Coupe T3 but at stock boost the power would be similar.

Kinugawa make a TD05H 16G 6cm with T3 flange. The wastegate actuator may need some re-jigging but otherwise should be an easy fit. This should spool up faster and is capable of more power