It's too nice to modify 😛 If i was gonna heavily mod, i'd rather a teenage kids beater car than a mint grandma mobile. I'd feel guilty messing up a car this clean. At the very least I'd keep the bodywork and interior mostly stock.
Then you've dumped $10-20K in a POS that you have to part out to sell.
Restomoded cars like this bring big bucks.
LS3, big brakes, suspension and buckets with Factory fabric, and its a $25K car in 5 years (and you make $10K on the deal).
Start with a high school kids POS and You'll have $25K in it and it will be worth less than $15K parted out.
Nobody should feel "guilty" they aren't driving around in a 150 hp squishmobile because it isn't still stock. 1981 was a long time ago and wasn't all that great, anyway.