Hopefully this will clear a few things up.<br/><br/>Virtual Reality plugs into your brain, basically like the Matrix movie.  Now, normally and legally, there's a bunch of blocks and safeguards which get put down.  That dulls the sensations to some degree, but protects you from major stuff.  For example, there's a Matrix program specifically designed to attack another user called Black Ice.  Some versions can do physical damage to hot sim users, but cold sim users only take stun damage.<br/><br/>In mechanical terms, hot sim is much faster.  You get three initiative passes instead of two, and you get a bonus to your initiative.<br/><br/>Now, a legal cold sim module is 100 nuyen.  A sim module modified for hot sim and BTLs is 250.  It's possible that your sim module has a switch to go between cold and hot sim and you just didn't realize it until now, so if you want to pay the extra 150 nuyen, I doubt Gary would object to the switch.<br/><br/>Modifying a cold sim module into a hot sim module is a Logic+Hardware extended test, 1 hour per roll, and you need 10 successes to finish.  Ruby's people shouldn't have much trouble doing it either.