Installation instructions:

http://thatpinballplace.com/documents/installing_eproms_wpc95.html

It's sometimes difficult to know whether an upgrade will 'improve' the game or not.

Sometimes, it's a huge improvement, like going from a really early TZ ROM to the 9.4H home ROM, or an early White Water revision to LH6.

Sometimes, the manufacturers released code upgrades to fix bugs in part of the ROM that the everyday player would never see - even more in home use. Perhaps an upgrade was released to support another coinage - or to fix spelling, or something similar like that.

Many newer games have documentation that explains what changed from one version to the next. The information, when available, is on the manufacturer's website. The Bally/WMS info that is available is here:

http://www.planetarypinball.com/mm5/Williams/tech/roms.html

Junkyard, specifically, is here:

http://www.planetarypinball.com/mm5/Williams/tech/roms/junkyard.html

From 1.1 to 1.2, you get the following changes:

1. German pricing updated.
2. Escape from DOG will score correctly.

So, the German pricing probably doesn't effect 99.44% of the JY users around the world, and the scoring on 'Escape from DOG' probably isn't a deal breaker.

There are also people who just enjoy playing the games, and don't care.

Anytime anyone has questions about ROMS, I'm glad to help if I can.