Q-Split Astro Spectra, what features to look for?

[oh2lna]

While looking for a Q-Split (403-438 MHz) Astro Spectra for the local 70 cm ham band, what models or features I should look for succesful P25 repeater operation?

There are Spectra radios on eBay without front panels and front panels without the radio. Are all the Astro Spectra models basically the same, if just the band split and flashcode are right and the host and DSP firmwares new enough? And those front panels interchangeable between different units as well?

And yes, our 70 cm ham band is only a mere 6 MHz slice starting from 432 MHz.