Stick with OEM all the way... Money will be well spent and you will have a happy car...
I've had mine for 5 years and she has never let me down once... All I do is get her serviced by a specialist every year & only fit genuine parts...
If you want to do her up look at the basics of what fails or fades on a 20-25 year old car...
New grille, new lights, new window rubbers, upgraded headlight loom. Check the tailgate for holes..
Sort the interior, ie bolster wear, carpets, car mats, rear parcel shelf and brackets.
Must have's for me (if money allows) ;Rear headrests (proper ones) electric windows & mirrors.
Other than that just keep on top of it and fix things before they go wrong...
You are driving a "Classic Car" at the end of the day - and if you want to get your money back you have to invest in the 1st place, and then you will have the fun of owning and MAYBE make a few quid at the end.
To me it don't matter what my car has cost or what it s worth as I will never sell it. If my kids decide to sell it when I'm gone thats up to them. but as long as I breath it won't be sold, for any amount of money!