The IR is way more effective than XR for recreational use. Which is why most doctors go for the XR these days. If you are trying to get your doc to start prescribing IR instead of XR, here is what you do:
A lot of insurance companies will not cover expensive, brand name, extended release drugs if there is a cheaper generic version of it.
Tell your doctor that you have a new insurance company does not cover the brand name XR, and to prescribe the IR so that you can get the generic. They're not gonna second guess you - it's completely logical.
Whether you actually buy brand name or generic Adderall IR is between you and your pharmacist, not your doctor. You just have to ask specifically for brand name. Not all pharmacies carry it, though.
I actually learned this from my doctor... we have a good relationship