I would suggest that you try it and find out. That doesn't mean that you go and buy SteveFX - DX10 Scenery Fixer just yet either! Just try doing as much of the tweaks as you can from the The "How-To" doc to see how it looks on your computer.

If, after doing that, it looks good and your computer performs well, you can then decide whether you think it's worth buy the DX10 Scenery Fixer to make the whole process a bit more simple.