Ive got an 80, I had the same quandry , keep the car original and end up with a real dog of a car or soup it up........
I dont think the low powered 1980 will ever be a real collectors item , that and the fact that I got beaten by 2 20something chicks in a Golf GTI (and they gave me the finger to boot) made me decide to soup it up. One more thing was that ANY american muscle type car or sports car is collectible in South Africa , there are VERY few vettes around and the market here demands both the looks and something in the "Broeks" (pants) and as an original , I wouldnt get a 2nd look if ever selling it.
Anyway , the mods I have done are these.
Willwood discs and Praggia 8 pot pistons, Swap 3:1 rear for a 3.55 rear gear , TCI 2600 stall, shift kit in the box , hurst promatic 2 shifter, Autometer Gauges , Decent semi racing seats and harnesses , delete aircon , edelbrock performer heads , ceramic coated headers , up comp ratio to 10:1 (using 64cc edelbrock heads) 280h cam , aftermarket dizzy , msd 6al, Steering and suspension overhaul, Performer intake , holly 770 street avenger carb , stainless exhaust system etc. I kept my old block from the L48 motor
Car is limited at 6000 RPM and is a blast to drive , its still streetable and now does a 12.8 1/4 mile on 265 BF tyres in Drive!!!!!
The 2 things that REALLY woke the car up were the diff change and the stall convertor.
I was considering putting in a crate motor , but it was very expensive to import one and was cheaper to do the rebuild , motor currently makes about 375 HP , dunno if the crate motor will give you that. apart from that , the motor serial no is part of our liscencing scheme here , and changing to a new block requires re liscenecing the vehicle , police clearance of the new engine and going thru roadworthy again....a major schlep.
You dont have to go as far as I have , but the one thing I would suggest is that whatever route you go , get a higher than stock stall convertor , it really does wonders for response and acceleration.
So far , with a nice spray job and new interior the car has set me back $11k , might be a lot for a 1980 in the USA , but I have been offered $25k for it over here....but wont sell , the grin factor is priceless.
Good luck with whatever you do.