I think the advice you've gotten is exactly right. But if you want to just have some fun with the car to find out how much you want to get into 914's I think that's also valid. Normally I wouldn't do this because these guys seem very, very cheezy, but they have something that might give you some ideas:
It's Red Dawg Racing
so if you shake hands remember to count your fingers afterwards to make sure you got them all back. I have no idea what they do to cool the engine, so ask. Or alternatively just weld up those targa holes yourself. Scars make your body more interesting, right?
It varies from state-to-state and I don't recall for sure but I don't believe that you actually have to have a DOT-glass windshield in California. Or it doesn't have to be stock or something. You'll need to research that yourself, but I think you can actually use aero windshields like some of the 550 Spyder replicas do (from spyderclub.com):
http://vintagespyders.com/parts/windshields.htmlhttp://www.fibersteel.com/ (in the "Body" category)
http://www.spydersports.com/http://members.shaw.ca/dman550/windscreen.htmlOr search for "spyder windscreen" on e-bay and see this:
E-Bay Plexiglass 550 WindscreenI seem to recall a requirement for windshield wipers, but the hot rod guys would put on little cut-down 4" wiper arms that they'd take off after the inspection and throw them in the trunk just in case. To be sure why don't you ask at www.spyderclub.com, they'll be able to tell you for sure.
Notice though that those windshields are all pretty expensive, so it might be more sensible to just weld yours back into it's general position, weld the targa panels back, assume the both won't ever be exactly right so not even worry about their alignment to fit in the targa top back in. Plan to not drive it in the rain, or instead of the targa top just use a sewn canvas bikini top between the windshield and roll bar. Have some fun with the car and then decide where to go from there.
As a note, the John Deere green enamel isn't THAT far from Ravena Green, and some of the industrial safety yellows aren't so far off what was on the car. At less than $50 bucks a gallon you can at least make it all one presentable color without any large commitment.
And finally realize that none of what I've said here is good advice. The others here have given you the good advice. But as long as you know the limits to resale value, return on investment, not winning concours events, etc, go ahead and have some fun. THEN use it as a parts car if that's what you want.
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