What do I need to know for the upgrade?

1) MSI Gaming G4
2) ~nothing really. might not hurt to get the latest drivers from nvidia, and make sure you fully uninstall your current gpu

MSI 4G is an excellent option however it seems more of a brand loyalty than factually better compared to others.

Unless you are going to do heavy overclocking the G1 Gaming seems to be an excellent option for the GTX 970.

Check it out:
http://biomtech.weebly.com/gpu-manufacturermodel-tier-list.html

Tier 1

Galax GeForce GTX 970 Hall Of Fame
Backplate: Yes / Base Clock: 1228 Mhz / Cooling: Triple Force

EVGA GeForce GTX 970 FTW+
Backplate: Yes / Base Clock: 1216 Mhz / Cooling: ACX 2.0+
Note: Slightly Better Overclocking Than Amp! Extreme Core, Memory MOSFET Cooling Plate's Are Great Quality.

Zotac GeForce GTX 970 Amp! Extreme
Backplate: Yes / Base Clock: 1203 Mhz / Cooling: Triple-fan IceStorm w/ Carbon ExoArmor
Note: Maximum Overclocking Is As Good Or Better Than The Amp! Extreme Core, This Is Recommended If The Price Of The Amp! Extreme < Amp! Extreme Core

Zotac GeForce GTX 970 Amp! Extreme Core
Backplate: Yes / Base Clock: 1228 Mhz / Cooling: Triple-fan IceStorm w/ Carbon ExoArmor
Note: Maximum Overclock Is Not As Good As Hall Of Fame, Most Likely Because Component's Used Are Not As Excellent As The Hall Of Fame & The PCB Was Not As Top Quality As The Hall Of Fame

EVGA GeForce GTX 970 FTW
Backplate: N/A / Base Clock: 1216 Mhz / Cooling: ACX 2.0
Note: Does Not Overclock As Well As The FTW+, Slightly Louder Than Other Models, However It Is Still Very Quiet.

EVGA GeForce GTX 970 SSC
Backplate: N/A / Base Clock: 1190 Mhz / Cooling: ACX 2.0+
Note: Overclock's GPU Memory Much Better Than FTW, Almost Identical Quality To FTW+. Maximum Boost Clock Is Lower Than FTW.

Tier 2

Galax GeForce GTX 970 EXOC
Backplate: Yes / Base Clock: 1164 Mhz / Cooling: Silence Extreme
Note: Slightly Better Gaming Performance Compared To G1 Gaming Before Both Are Overclocked. Great Cooling.

Gigabyte GeForce GTX 970 G1 Gaming
Backplate: Yes / Base Clock: 1208 Mhz / Cooling: WindForce 3X
Note: Excellent Cooling

Tier 3

EVGA GeForce GTX 970 SuperClocked
Backplate: N/A / Base Clock: 1165 Mhz / Cooling: ACX 2.0
Note: Overclock's GPU Memory Much Better Than FTW, Almost Identical Quality To FTW+. Maximum Boost Clock After Overclocked Is Lower Than FTW.

Zotac GeForce GTX 970 Amp! Omega Core
Backplate: Yes / Base Clock: 1102 Mhz / Cooling: Dual-fan IceStorm w/ ExoArmor
Note: Good VRAM Overclocking.

MSI GeForce GTX 970 100 Million Edition
Backplate: Yes / Base Clock: 1140 Mhz / Cooling: Twin Frozr V
Note: Basically MSI Gaming Edition + Backplate + Color Change

MSI GeForce GTX 970 Gaming 4G
Backplate: N/A / Base Clock: 1140 Mhz / Cooling: Twin Frozr V
Note: Hotter Core Compared To G1 Gaming. Good VRAM Overclocking.

Gigabyte GeForce GTX 970 OC 4GD
Backplate: Yes / Base Clock: 1149 Mhz / Cooling: WindForce 3X

Palit GeForce GTX 970 JetStream
Backplate: N/A / Base Clock: 1152 Mhz / Cooling: JetStream
Note: Worse Overclocking Compared To SuperClocked. Build Quality Is Not Good.

Asus GeForce GTX 970 STRIX
Backplate: Yes / Base Clock: 1114 Mhz / Cooling: DirectCU II
Note: Overclocks Slightly Less Than MSI Gaming 4G.

MSI GeForce GTX 970 4GD5T OC
Backplate: N/A / Base Clock: 1102 Mhz / Cooling: Armor 2X
Note: Components Are Solid, However Cooling On Everything Except Core Is Not As Good As Gaming 4G.

Oh yes! The SSC is an excellent option. GPU overclocking is easy and safe, you can use the guide on the bottom right of this reply to do it!

CX series are highly unrecommneded. They use poor quality Chinese capacitors and have terrible quality components. They are not ment for gaming builds.

Excellent Choices:
EVGA GS 550W
XFX XTR 550W
XFX TS 550W
Seasonic M12II 620W