I bought a Bi-Xenon kit (6K) from Ebay (Xentec brand) for $52. I also purchased a fog light kit (6K) for $32. I installed everything myself, and only took me about 1hr & 20 minutes because it was my first time working on a ford truck. HID kits are very inexpensive now a days, and honestly they are all made with very similar materials. Spending $350 on one kit is overboard, IMO.
As far as light output, I am obviously using my stock head lights and fog lights, and the improvement is very noticeable. The fog lights look amazing. The headlights do have a higher output than with original bulbs, but the light output is scattered, as opposed to the fog lights. I have not had time to play around with aiming the headlights, but i plan on doing this very soon. If this doesn't improve the light output, then i will consider doing a retrofit myself with some good halogens. The headlights don't look bad, but they could be better.
If i were you, i would refrain from getting the 55w bulbs and just go with the 35w conversion. The 55w will only shine brighter for a short period of time (a couple of months, at most), then the output will diminish just a tad lower than the 35w bulb. Also the 55w kit is more prone to failure, due to the higher power draw. Google search this if you like. Just my 2 cents.