Here's what I use on my Tahoe:
Lund Winter Front.
They're just cheesy pieces of plexiglass-like material, but they work really well. You just snap them into the grill. Mine came in 6 sections, so you can choose how many to add. I've had all 6 in for most of the winter, and it keeps the engine right at optimum temperature, and speeds up the warming process as well. They look pretty cool too.
Casey
1995 K1500 Tahoe 2 door, 6.5LTD, 4L80E, NP241, 3.42's, 285/75R16 BFG K02's; 1997 506 block; Kennedy OPS harness, gauges, Quick Heat plugs, and TD-Max chip; Dtech FSD on FSD Cooler; vacuum pump deleted, HX35 turbo, Turbo Master, 3.5" Kennedy exhaust, F code intake; dual t/stats, HO water pump, Champion radiator; Racor fuel filter