First off, you HAVE to download HI-RES if you want to enable 1024 textures (if you don't, even though you select 1024, you'll really only have 512). If you select 512, the HI-RES doesn't make any difference.
As far as soundpacks go, there are many you can choose from... personally I use the MITSU soundpack, but there are several (Just do a forum search for Sound Packs).
Then there's the Map Editor utility.. pretty much useless now that 8 player is no more... and I've tried playing around with it a few times... it's just too confusing for me.
And lastly, there is a Pilot Stats/Aircraft performance software you can download that will pull info off of the servers and graph everything out all pretty for you. I just got these the other day, haven't had a chance to really do much yet (You can download these
HERE .