not a lot more i can explain mate.
easily the best thing about the sp1 is the bolt out the back. a clean will take 5 minutes max. my delta elite took me about an hour to clean properly, it was a nightmare
then theres the 3 round burst. its so badass =P
oh... run it on HPA
take a look on gommie404's thread here:
http://www.ukscenario.com/forum/viewtopic.php?f=11&t=14514
he upgrades sp1's to an amazing level. if you decide on getting one i would speak to him, he knows his ****.
you might even be able to buy one from him.
man that would be awesome.