should I fix it?

and wich one are the most important?

my host is godaddy.com and not seems very easy to enable them…

mod_deflate: Not detected (required for disk enhanced Page Cache and Browser Cache)
mod_env: Not detected (required for disk enhanced Page Cache and Browser Cache)
mod_expires: Not detected (required for disk enhanced Page Cache and Browser Cache)
mod_filter: Not detected (required for disk enhanced Page Cache and Browser Cache)
mod_ext_filter: Not detected (required for disk enhanced Page Cache and Browser Cache)
mod_headers: Not detected (required for disk enhanced Page Cache and Browser Cache)
mod_mime: Not detected (required for disk enhanced Page Cache and Browser Cache)
mod_rewrite: Not detected (required for disk enhanced Page Cache and Browser Cache)
mod_setenvif: Not detected (required for disk enhanced Page Cache and Browser Cache)
Additional Server Modules

New Relic
PHP version: Not supported: 5.5.38. Supported versions are 5.2.x, 5.3.x, 5.4.x.