Bass friends ... I recently purchased the Mesa Subway D-800 + and now less then a year later Mesa has come up with the WD-800 Amp that features a tube pre amp and parametric eq. I'm having a blast with D-800 + so why would I want to upgrade to the WD (?) I'm rolling a Subway 115 Ultra lite Cab and soon to add the 210 on top. Other then a severe case of GAS (that I usually can control) why should I or shouldn't I upgrade (?) Also is this an upgrade or just a different animal of an Amp (?) Thanks for your wisdom and wit in advance.