Bug Bombing / spraying cars

Reaching out to the community here to see if anyone has had good results with using bug bombs (foggers) or spray on cars full of six or eight legged hitchhikers.

Some context; I recently acquired a 1981 Fiat 124 Sport Spider, and true to the name, this old italian stallion is home to a large variety and quantity of spiders, inside and out. I'm at the stage where I need to put the car on stands and pull the engine, which would put me underneath the car, on a creeper, with all those arachnids... While they're mostly harmless, judging from the webs I've seen and my location, there could be a few black widows in the mix too. So logically, I want to kill off as many spiders as possible before I get moving on this project. 

My plan is to push the car out of the barn, put one bomb/fogger under the car, one on the drivers floor, and then (with the top down), drape a bunch of old tarps over it to keep most of the insecticide in.  That said, anyone been in a similar scenario and successfully eliminated most of the bugs/spiders?

No experience (EDIT: no experience trying to bug bomb a car; plenty of experience being freaked out by bugs, especially spiders, in cars and shops), but I'm faintly concerned about the effects on plastics.

You might inquire with one of the places that specializes in DIY pest remediation, or even a local pest exterminator. We had a bad go-round with an ineffectual branch of a big chain, but have since found a local guy who's a bug geek (er, entomologist) in the best way. One of those might be able to figure out the best way to debug your car with a minimum of collateral damage/residue etc...

We bought a Mazda Five that was infested with German cockroaches. We still have it. No roaches after that. 
GRM forum discussion

Bifen is effective for spiders. I think that other insecticides aren't.

My e36 sat in the driveway under a cover for a long time before i actually started working on it. A whole bunch of spiders, many being black widows, took up residence in the nooks and crannies. I got the car on my quickjack and carefully scooted under it so i could spray insecticide directly into the buggy spots. Worked great, had a bunch of dead spiders under the car shortly afterwards. 
 

for in the car, im a fan of pulling the carpet out. 
great opportunity to clean the carpet and seats and flush out the buggies. 
 

another possible idea. Let some chickens hang out around the car. They love to eat spiders and german roaches.