The noodle-technique is a very popular option owing to the relative frugality of the approach ($2) versus the original horsehair pad ($120? each). Very popular in w123 circles.
However, noodles are more useful for propping up springs in saggy seats as opposed to lumpy. Assuming you can't turn the other cheek, you might need to creatively add pieces of the noodles to counter the lumps.
I hate to be cheeky :mrgreen: <duck>, but if you plan on driving longer distances, I would advise you take the new seat-pad route.