KJW 5.1 upgrade list help.

[BlackJack]

Could the pistol guys look at this list and tell me what is a drop in on a KJW 5.1?

9ball hicapa grip-black
http://www.airsplat.com/nine-ball-tm-hi-capa-custom-grip-black.html
Inner barrel (112mm)
http://www.redwolfairsoft.com/redwolf/airsoft/Accessories_Precision_Barrels_GBB_PDI_01_Precision_Inner_Barrel_for_Marui_Hi_Capa_5_1.htm
Nozzle spring
http://www.evike.com/products/47639/
Bucking
http://www.evike.com/products/43059/
BBU
http://www.evike.com/products/51972/
Slide
http://www.a-airsoft.com/index.php?route=product/product&path=65_69_119&product_id=500

Thanks