TM hi-capa 5.1 vs ksc usp compact

This would be my first airsoft gun, yes i know get an aeg if you want to get into the sport, but at the moment i have other things to worry about (which are none of your busness to put it nicely) I've already made up my mind on that topic, im going to get a gbb and see where it takes me. (hopfully i will have the $$$ to continue buying airsoft and participate in a few games within the next year)

Now i know with the compact i wouldnt be able to use propane unless i got the metal slide, and maybe upgraded my recoil spring (is the spring even avail?)

As for the hi-capa i dont know if there even is a metal slide in existance, :-? From what i know the only way to upgrade TM's is to use parts from other brands. (ksc / kjw) That statement however is based on my knowlage of the TM glock26. As a side note what gas would i have to use for the capa? my friend owns a TM glock26 he used it on propane for 3000+ rounds before the slide broke, and it actually didnt break off, just cracked in a very crutial place

My main concern is realibity, and durability. I DONT WANT A GUN THAT WILL BREAK :banghead: I AM aware that you MUST take very good care of these guns in order for them to last long, so i am willing to put more money into upgrading parts.

NOTE: if this IS in the wrong section im very, very, very! sorry. I know how touchy people can be on this site about the smallest detail. If a mod can just move my post that would be great!
- Alex