Hi what do people use on there Vitara if they want to use a in line air filter between signal point injection and snorkel ? I need to relocate the are filter so I can fit a second battery for my winch.

I've used a pipecross venom canister filter. I was going to fit a second battery but as the winch is rarely used I opted for a deep cycle 100ah Numax battery relocated to the opposite side of the engine bay.
I would post a picture but I've forgot how to.

indeed, unless you're doing a LOT of winching, a single battery should be fine