Depends on the type of riding you do and the overall shape your machine is in.
The 400 2 stroke is a good motor.
A suspension lift wouldn't be a bad idea but you've still got the sprocket hanging down out back.............what you may really need is more ground clearance, so TIRE IT UP, but if you went to 27"s, you need to get different back rims(go to 12"s) and still only gain about an inch in clearance on the rear.Plus clutchin' or sprocketing down. Tough call indeed
Since it's a lil older you'll probably be able to find a new or used winch bumper and plate on ebay.
'08 Sportsman 500HO efi
'14 RZR 800 trail
'03 sportsman 500HO (gone)
'14 Massimo 800
'08 Hisun 700(gone)
'02 expedition 425(gone, but missed)
'98 Sport 400 (gone)