see if you can obtain an VW rabbit cab dash the lower section sticks out, a lot more beefier and houses your power switches in that little tray under the ashtray, they also had the fancy air con keep cool with the rag up too. retrim in leather, some german style pressed metal number plates look nice. they even had a nice porsche style leather wheel on the last ones, americans get all the fancy gear, although they are cursed with them shocking large indicators and side lights.
Get your electric windows switches to operate the back windows when you fully crank down the front without using additional switches, theres a challenge.
all else fails stick a "i brake for no one sticker in the back window"
mod something too much surely it stops being the quirky car you set your heart on in the first place.
sometimes you turn heads for it being what it is and perhaps not how big the roof spoiler or furry dice are. you look at a GTI badge any design and its instantly pictured with a golf, look at an SR badge and your probably scratching your heads going aint that short for sunroof?
just a thought
your motor looks sorted maybe its time for a new project or time to enjoy your creation