OBD2a/OBD2b Integra:

Engine Installation:
reuse all existing engine brackets/mounts/axles/shift linkage

Wiring:
Reuse existing EWH and follow wiring info for 96-98 civic for 96-99 Integra's or 99-00 Civic for 00-01 Integra's.

**OR**

You can actually use a US OBD1 engine wire harness in a 96-01 integra. You heard me right. 96-01 Integra's all retain a 2-piece wire harness design. Honda thankfully made the break off plugs backwards compatible with OBD1 EWH's.

So, if you can get your hands on any one of these OBD1 VTEC EWH:
94-95 integra GSR
92-95 civic Si/EX
93-95 DOHC Delsol

...you're all set..
Just make sure that if you own a non-VTEC integra that you have VTPS, VTS, and the KS wired in from the ecu plugs out to the shock tower plug and you'll be golden.

ECU:
Note: 96-01 OBD2 integra's all have the 2nd 02 sensor integrated into the cabin harness, so there's no need to wire in a 2nd 02 sensor at all for 96-01 integra's.
00-01 Integra ecu's are immobilizer equipped and cannot be swapped around unless the IMM is removed.

- (96-99 Integra) JDM OBD2 ecu (direct PnP). Same PRO/CONS as 96-98 civic w/JDM ecu.

- (00-01 Integra) JDM OBD2 ecu (OBD2b>OBD2a jumper harness required). Same PRO/CONS as 96-98 civic w/JDM ecu.

- (96-01 Integra) OBD1 ECU conversion; same PROS/CONS as 96-00 civic OBD1 conversion.

- (96-99 Integra) OBD2a US ECU; PnP; same PROS/CONS as 96-98 Civic.

- (00-01 Integra) OBD2a US ECU; same PROS/CONS as 99-00 Civic.

- (96-99 Integra) OBD2b US ECU; OBD2a>OBD2b jumper harness required; 00-01 integra ecu will need to have the immobilizer removed in order for 96-98 Integra to run.

- (00-01 Integra) OBD2b US ECU; 99-00 Si ECU will be PnP pin A15 needs to be moved to A16 for fuel pump operaton; 00-01 integra ecu will need to have the immobilizer removed in order for car to run.

Read more at http://honda-tech.com/showthread.php?t=1972711&kcplink=1