Congrats on the purchase - a fun game.

I lean towards Pascal boards as they are "all in one" and most chips are socketed. No ground mods are required other than one small screw in terminal on the board - that's easy !

The "PI-FX/X4" is suited to BR. I bought one for a Genie I restored a while ago and it was a huge improvement.

Now a word of caution - the connector pins will most likely be tarnished of corroded. These should be replaced. If they are corroded, then the corrosion will creep up on your new board.