Best bet is go to the 356 registry and ask away there or Pelican Parts forum. What do you need to know?
Throw a few questions up. I know of three guys here that have a pretty good handle on the 356. Try us.
What is the value of a 1962 356B twin grille roadster and an early 1957 speedster? Both cars restored in perfect condition
Twin grill. Rare. $150k+ Bullfighters input will be paramount as I am certain he is on the market for these. With that said the next Gooding auction has an exceptional '58 Speedster (ex-Jerry Seinfeld) with an expected $300-$400k sale price rolling through Aug 18th at Pebble. Plus another very good '58 with an expected $200-$250k bid.
The 356B T6 roadster is a rare car, with only a couple of hundred made. There's a perfect bali blue over red one for sale now and I don't think it will be bought for under $250K. It's restored to the level where you could eat off the suspension. You didn't mention the chassis number of the Speedster, but if it is 83201 or later it should have the teardrop style tail lights (about March '57 production). "Early" ones had the beehive style. If it's "perfect" -- meaning a solid bare metal restoration, perfect gaps on all moving panels, original floor pans/longitudinals, correct exterior/interior colors, correct and numbers matching 356 engine/gearbox, etc., it's also easily a $250K+ car. (If it's an original Carrera Speedster, probably more like $500K+.) You would want a documented (with ample photos) restoration to substantiate that it's not pretty paint over bondo. If the original color indicated on the Porsche CoA is silver or black, and/or the orginal engine was a 'Super', some buyers will pay a slight premium. As mentioned above, the 356 Registry is a good place for a price check. I'd also call out Registry member Bob Lee as an especially knowledgeable guy when it comes to these cars.
nice little pca event here on shelter island today. some very high quality 356's being displayed and judged. i hope to see jon's car displayed soon!!! pcb