Being a street car, I would still suggest looking into going power steering.
The improved steering ratio will put a lot of fun and ease back into the car it you want to do some occassional quick cornering.
The current Borgeson P/S boxes aren't that much larger than a manual box. But I can understand that space is already almost non-existant as it is.
If you don't want to add a P/S pump on the engine, you can always look at using an electric hydraulic pump.