Look airsoft sites, there may be high end valve upgrades for it. Metal slides for Desert eagle, if there is any, are probably real pricey. Have a look around websites like
www.wgcshop.com or
www.redwolfairsoft.com. They should have something for the desert Eagle.
Took some time to help you out, here is a reinforced hammer for your Deagle
http://www.wgcshop.com/WGC_Shop/images/km_tm021de.jpg
It is made buy KM
KM stainless valve knocker
http://www.wgcshop.com/WGC_Shop/images/km_tm08den.jpg
Guarder enhanced feeding muzzle
http://www.wgcshop.com/WGC_Shop/images/gd_pt_mu04.jpg
Nine Ball ahmmer spring
http://www.wgcshop.com/WGC_Shop/images/nb_pt_dehs.jpg
Proud enhanced recoil spring
http://www.wgcshop.com/WGC_Shop/imag..._acc_pis18.jpg
Zeke metal Frame *it is paint white due to japanese gun bans, you will need paint remover to get the metal color*
http://www.wgcshop.com/WGC_Shop/imag...sl_tmde5mf.jpg
Zeke Metal Slide
http://www.wgcshop.com/WGC_Shop/imag...sl_tmde5ms.jpg
I just searched WGCshop for all this, theyhave lots of goodies for your Desert eagle, these are njust some slected few i found. Just type in Desert Eagle in the wuick search, it will pop up pretty much everything for Tm and Digicon Desert Eagles.