Ander,Welcome to our Addiction.....The best thing you can do with that new gun is clean the barrel with googone, make a bore snake out of a piece of heavy weedeater line, melt one end and flatten then make the other end pointy, use that to pull patches through your barrel, use a drinking straw to get it past the break on the muzzle. Do that until you get clean patches, then buy a tin of cheap Crosman Premier Hollow Points (CPHP) from Walmart and shoot them all through the gun, this will get the barrel seasoned and ready for some testing on what types of pellets the gun likes to shoot, that will require you to either buy a sample pack or buy a bunch of tins or pellets, PA has a special buy 3 get 4 free.Add another vote for the CDT III Trigger and Barrel Bushings...
first things first, give the bore a thorough cleaning with goo-gone to remove the gunk. run dry patches through until they come out clean. never use petroleum based lubricants, and never oil the compression chamber. check all the stock mounting screws and you may even want to secure them with a little blue lock tite.it takes several hundred pellets before these guns settle down, so be patient. mine shoots h&n ftt best, followed by rws super h-points. your results will vary.as to upgrades, a GRT-III trigger blade is a must, as are pivot washers from gene_sc (airguntoys.com)eventually you'll want to upgrade the scope and mount.