I have recently upgraded my suspension on my 06 D22 with Tough Dog front and rear shocks and also Tough Dog torsion bars. This is in addition to a 2'' raised rear end with an extra leaf added. I also tow a Jayco Swan ,approx weight 1500kg fully loaded. The entire set up cost about $1200. Shocks and torsion bars from opposite lock for $900 approx. Has been a huge improvement to overall handling on and off road and a major difference with towing. Is a lot more sure footed over corrugations an generally rough roads with or without the van. Hope this helps anyone. 
