So basically you would be switching from Toytec's Boss coilovers to their Ultimate lift coilovers. The red coils from the boss shocks won't work with the 5100's unless you have Toytec's adjusting collar (threaded anodized aluminum pieces in the photo below). The red springs are designed for adjustable coilovers (they are flat on the bottom). Bilstein's spring perch is designed to work with coils with a pig tail bottom like the OEM springs or Toytec's 521600 or 112620 coils. You'll either have to get Toytec's adjusting collars to run the red springs you currently have, or run the OEM springs, or buy new springs.