Damn Simplygon. It crapped out on my lappie too and Meltfire's fix didn't work.
Sorry for the rant.
Hope it helps as a starting point, here's the list of materials in case a kind soul is willing to make LODs for PedroBLR's Mazda Motorsports RX-7 1991 so that our good folk Alguecool can work his magic on a skinpack. The car can easily be found on YT.
paint: material:livery_002, material:livery_001,
interior: material:net, material:int_cloth_blk, material:int_metal_gray, material:int_cloth_blk, material:int_chrome, material:int_metal_blk, material:hole, material:int_rubber, material:int_plastic_blk, material:gls_window_interior,
material:Material #27, material:int_glass, material:int_red, material:grill_005_red, material:int_seat_1, material:int2_plastic, material:int_blue, material:symbols, material:gauges, material:embossed, material:int_green, material:int2_metal_gold,
less important: material:hole, material:int_rubber, material:int_orange, material:int_plastic_blk, material:int_glass, material:int_red, material:int2_plastic, material:int_blue, material:symbols, material:gauges, material:embossed, material:int_green, material:int2_metal_gold,
important: material:Material #26, material:ext_rubber, material:ext_chrome, material:screw, material:grill_005_alpha, material:int2_metal_blk, material:black, material:int_metal_gray, material:int2_chrome, material:gls_window, material:tail_glass, material:tire, material:rim_chrome, material:rim_base, material:rotor3, material:rim_inner, material:net, material:int_cloth_blk, material:int_metal_gray, material:int_metal_blk, material:int_chrome, material:gls_window_interior, material:Material #27, material:grill_005_red, material:int_seat_1,