my friend's LS2 Powerd S14 Still Hase ABS/Airbag/AC/PS...and now he is swaping a 550whp LS7 engine....
So yes...you can keep your ABS WITH the LSx...
Also what mount kit are you usuing....? there is a company that offer a mounts kit + Trany Mount + Oil relocat and other stuff for 1750$...

WITHOUT cutting the stock cross member.... :love
Check silviav8.com for more info

..
Hope This Help,
Regards,
Ali