06 WRX is the Same as the 07 STI. Here is what you need to get started. This is 95% of it and the rest is know how on electronics and wiring. You need ECU, Immobilizer, Antenna, Key, DBW pedal, Fuel pump controller, complete wiring, motor and everything attached to the motor. There is alot of pictures and links in my sticky at the top of the swap forum!
Conversion From 2007 STI to 1999/2000 RS Pinout
Description - STI pin location - RS pin location
VSS B136/13 - B135/24
Backup power supply B135/5 – B136/9
Starter Switch B136/32 - B135/28
Ignition Switch B135/19 - B135/7
Neutral Position B136/31 - B135/26
Test mode connector B135/27 - B135/14
Line end check - nothing
Control Power B134/7 - B136/1
Control Power B135/2 - B136/2
Evaporation Thermo Switch B136/24 – B135/27
A/C relay B136/9 - B134/17
Fan1 Relay B136/18 - B134/3
Fan2 Relay B136/29 - B134/12 *Changed from actually wiring diagram one says pin2*
CEL light B136/11 - B134/11
Tach B136/22 - B134/30
fuel tank pressure sensor B135/32 - B136/12
Fuel tank pressure solenoid B136/28 - B134/1
Drain valve B136/17 - B134/10
Fuel tank valve B134/24 - Not on the RS body
Fuel level sensor B135/10 - B136/27
Fuel temp sensor B135/17 - B136/26
Small light B135/15 - B136/3 (Doesn’t exist on 99 RS only on 2000+)
Blower fan switch B135/16 - B136/30 (Doesn’t exist on 99 RS only on 2000+)
Rear defogger Switch B135/14 - B135/21 (Doesn’t exist on 99 RS only on 2000+)
SSM/GST Communication line B136/16 - B135/3
5Volt Power supply B135/22 - B136/15
Immobilizer B136/26 - Immobilizer/Pin10
Immobilizer B136/34 - Immobilizer/Pin23
Self Shutoff Control B136/23 - B135/19
AT/MT identification signal – T’ed to ground
CAN communication + B136/27 –
CAN communication – B136/35 –
*Not complete still need powers and grounds and randoms*
Addition Wiring on the 1999/2000/2001 RS harness:
OBDII Connector Pin4 B135/11 (G/W) - Not Used for the STI
OBDII Connector Pin5 B135/12 (Lg/R) - Not Used for the STI
OBDII Connector Pin8 B135/21 (W/R) - Not Used for the STI
Line End Check 1 B135/20 (R/W) - Not Used for the STI
Fuel Pump Relay Control B134/16 – B135/19
^^^****The Opposite side of the fuel pump relay now needs to be ground instead of power. The Main Relay needs to be power instead of ground. This can be done by swapping the Main Power Relay and Fuel Pump Relays power and ground. These are the wires opposite the side that go back to the ecu****
W/G RS >>>Water temp>>> W/G STI to dash gauge
G/W or G/B RS>>>>Oil pressure >>>G/W STI to dash light.
2007 STI Fuel Pump Controller
R122/1 (B) - To the ground leading to the fuel pump (B)
R122/2 (V/W) - Wired directly to the ECU
R122/3 (B/Y) - Wired to the 12Volt power leading to the fuel pump (B/R)
R122/4 (B/W) - Wired to negative side of fuel pump (B)
R122/5 (Lg/R) - Wired directly to the ECU
R122/6 (B/Or) - To positive side of fuel pump (B/R)
2007 STI Cruise Control:
B135/3 - Set light on dash - B161/6 (B)
B135/6 - Cruise light on dash - B161/4 (V)
B135/12 - Cruise button on - B94/4 (Br/W)
B135/13 - Resume/accel - B94/7 (R/W)
B135/20 - Brake switch 12v switch - B94/8 (R/Y)
B135/24 - Set/coast - B94/6 (Lg/B)
B135/28 - Brake switch 12v switch - B94/19 (W/B)
B136/25 - Clutch switch - B94/9(L/Or)
B94/5 (Y/G) spliced to B94/3 (G/B)
B161/2 need to be T’ed to B161/1
B107/1 needs to be T’ed to B94/8
Immobilizer Pinouts:
Pin 1: Antenna
Pin 2: Fused 12v power (Power into Main Relay)
Pin 3: Fused 12v power (Power into Main Relay)
Pin 5: Security Light on dash ???
Pin 8: Door light switch (Yellow wire from doors, color is the same on 07STI and 99RS)
Pin 9: Keyless entry wire but T'ed to impact sensor. This does not exist on the 99 RS. But I think you will be ok.
Pin 10: ECU wire (B136/26)
Pin 14: Antenna
Pin 15: Ground (B134/5)
Pin 23: ECU wire (B136/34)
Pin 24: Ignition fused 12v Power (Power into Main Relay)
Pin 25: Ground (B134/5)
Pin 26: Ignition Starter & Steering Lock assembly (B135/19)
IF YOU ARE NOT 100% SURE YOU CAN COMPLETE THIS I WOULD SUGGEST CALLING ECS TO HAVE THE WIRING MERGE DONE!!!!