None other than the downgraded spring they installed before shipping and a good once over to make sure everything was in working order. Unless you consider the Proper assembly and a good Lubing a mod. Im getting 462fps with .20 Bastards. With .30 Bastards im hitting a 4 inch target 9 outa 10 times at a 100ft. As far as reliability well ya got me there it will be used heavily this year and without mods or upgrades till it breaks if it breaks.
Last edited by Spawn28; May 2nd, 2011 at 00:31..