We just bought a 2003 3500 ram, 5.9 of course. There is no transmission temp gauge. 1. Should we add on a gauge or gauges (what others?) 2. Should we add on a tranny cooler and if so , is there a good brand? 3. There is a 3rd party fuel / water filter system, supposed to filter down to 2 microns. Is this a good idea or just replace existing ones with better filters? 4. The prev. owner suggested bags to give extra support to the suspension. If the intent is to pull a 5th wheel, maybe 13,500 to 15,500 GVRW, is this necessary or will it be better for it? Thanks for any help.