If you're changing to a narrower body and/or want to relocate the electronics to the center on your TRX4 I would suggest this. It made my swap on my sport easy. From Crawler Innovations. You'll need longer screws though which are not supplied.
https://crawlerinnovations.com/traxxas-trx4-front-electronics-tray/
https://crawlerinnovations.com/traxxas-trx4-front-electronics-tray/