a) this is in the wrong thread
b) you don't "buy" mods for your guns mods are stuff you do yourself i think you mean upgrades.. if that's what you mean then i would suggest a new barrel (spyder is famous for having HORRIBLE stock barrels) other than that it really depends on what you want you gun to improve on..
c) a halo on a spyder electra?? seriously, instead of getting two ok guns you should spring for one gun that's more pricier, i have a promaster that i LOVE and it's only $140 on actionvillage.com everything about it is great, except it doesn't come with an asa.