Northstar to LS3 Swap - Any issues?

[wesinls]

First off, the car is a mid-engine...pics below from when it was it...For those that have gone through it - are there any major gotcha's?  I'm wanting to purchase an LS3 - remove the Northstar - install the LS3 mounted only to the S5 tranny, then bring it to a shop to help with motor mounts, wiring, etc.  I havent yet compared measurements, but I'm wondering if the LS3 will be longer and as a result i might not be able to get it in the car?

Any help or pointers appreciated.  

Ty!
 

 

[Pennywise]

The LS3 is longer, your water pump is on the back of the motor & LS3 is in the front so you have to allow room for water lines too