"Flippin Fearless" looks like an older Nacra 5.2. The Nacra 5.2 had the center bar that ran between the center of the front and rear cross beams, had no brial foil, had a boom (vice boomless 5.5) and had straight spreaders on the mast instead of spreaders that angled towards the rear. But I am not personally familiar with "Flippin Fearless"

I agree with the mods on the original post except for removing the bridal foil. It is supposed to reduce the stress on the hulls. The other advantage was to have a lower jib attachment point so you could have more jib sail area. The 5.5 does have an overlaping jib (goes past mast) but it not nearly as large as the Nacra 6.0's jib. If he would be using the spi extensively, the jib size could be reduced to allow for the self tacking jib without affecting much. I did not add self tacker, but hooked the jib bocks to the tramp to get rid of the wire across the deck. The Spi poll can be put under the bridal foil without problem. I do not know how much spi load the mast will take. I only run my spi at light to moderate breeze (up to 12 mph) because I am afaid to stress the mast more as it was not designed for the spi.

My Nacra 5.5 modifications are at nacramania.com