KART M14 Upgrade Path

Looking to invest into a long range gun and I've always loved M14 EBRs so I decided to get a KART EBR and upgrade it since it seemed like the cheapest route to go for me.

I'm getting mixed feedback from people on what I should do to upgrade the internals. Should I go with a Guarder SP120 FTK or get the items on the list below? Thanks for all the help in advance.

Guarder FTK
http://www.airsoftextreme.com/store/inde....roducts_id=3525

Individual Parts

Guarder SP140 spring
http://www.airsoftgi.com/product_info.php?cPath=31_51&products_id=3390

MadBull Ver. 2 Precision Inner Barrel for M16
http://www.airsoftgi.com/product_info.php?cPath=31_55&products_id=1231

Element 300% MAX Helical Torque Gear Set for Ver. 7 (TM M14)
http://www.airsoftgi.com/product_info.php?cPath=31_49&products_id=4181

Prometheus Hard Piston for Ver. 7 (M14)
http://www.airsoftgi.com/product_info.php?cPath=31_148&products_id=6616

Modify Version 7 Spring Guide with Bearings
http://www.airsoftgi.com/product_info.php?cPath=31_268&products_id=3617

Systema Area 1000 Cylinder Type 0
http://www.airsoftgi.com/product_info.php?cPath=31_52&products_id=147

Prometheus Aero Cylinder Head for Ver. 7
http://www.airsoftgi.com/product_info.php?cPath=31_52&products_id=5615

Systema Aluminum piston head with bearings
http://www.airsoftgi.com/product_info.php?cPath=31_148&products_id=150

Systema Hop Up Bucking
http://www.airsoftgi.com/product_info.php?cPath=31_170&products_id=421