who makes the best carbonfiber Porsche parts, especially for a 993

What kind of parts? Alot of carbon fiber parts will be trim accessories (such as door sills, gear shift knobs, etc). These parts r made by all the companies you'd expect to offer such items, & the quality u can expect from these would be the same as u would for any other items they might offer (ie, Momo is more of a quality name for a gear shift knob than the local auto parts store in house brand).

Race shells? Sparco & Recaro would be the main companies in this space. Carbon fiber will definitely be the lightest here, though wear & tear lead many racers to look at other kinds of seats (tough to justify a few thousand for a seat every couple years).

Bodywork? A few companies offer parts, though they r often hard to evaluate. Most of the companies that do bodywork fabrication for Porsche seem to use fiberglass as their lightweight item of choice, & these r the parts l see most often on racecars. Though there r some carbon fiber parts out there, which will be marginally lighter than the fiberglass (for alot more money). The best bet here is to find a Porsche bodyshop that is an expert with Porsches (ask around with PCA members in ur area), & then talk with them about the items u want & which they have seen that have been both well made & have had the best fit & finish when done.