I have two 455's in .17 HMR; both threaded, and suppressed. One is a 20" fluted varmint barrel; the other a standard 'American' profile barrel cut down to 16.5".
I run SiCo Sparrows on both.
I have noted no major difference in either rifle with or without the suppressors.

I've swapped glass since that picture was taken: current specs of the rifles without suppressors on them:
CZ455, 16.5" sporter barrel, Nikon Prostaff 5 4.5-18FCD. Factory walnut stock. Unloaded weight 6lb 13oz
CZ455, 20" varmint fluted barrel, Nikon Monarch 3 6-24FCD. Boyds 'Tacticool Stock.' Unloaded weight 9lb 1oz
For me, when I go out to eastern MT killing gophers, and I want to go walking around for a while; the lighter rifle always goes. a few pounds starts to be noticed on a 5 or 6 mile walk.
The other benefit of getting the threads cut your way, is you can get them cut to SiCo's spec (available on their website) so the cut is made for the oring, so you're not constantly chewing up orings.