To upgrade your subscription to include Stack Speed, you will need to purchase The Stack Hardware and enter your Serial Number in the Stack Speed tab of the App.  Once that is complete, you will receive 2 years of included access to all modes of the App.  After 2 years, you can continue enjoying all modes of the App for $99 annually.  We encourage you to utilize our Referall program too, which gives a discount to your friends on the hardware and for each referral, you'll get +1 year access to the App.