I retain all of my stock options with my gen3 except cruise control. I also didn't have to buy an SAFC, or water injection kit, and the only reason you don't "need" a boost controller with an SDR is because you can elect to drop another $200 on a boost control soleniod for the computer (more than what I paid for a profecB). There is no need for a standalone on a gen3 if you want 320-ish rwhp like I do. The arguments in favor of a standalone for a gen2 don't apply for the gen3. There is no AFM to delete, the turbo already rocks, it comes with 550cc injectors, and runs 12's out of the box. The argument that an SDR "only" costs $1000 is also a little fishy. That will get you the box, but add a few options like the wideband and boost control solenoid and you're up to $1500. Add full dyno tuning and it will cost at least $2000. The biggest point is that 320rwhp will get an mr2 near 11's while other cars would still be in the mid 12's (In most cases, I know everybody has a friend who ran a 9.99 with 145rwhp so don't get stuck on that single point).

Now, if you have a gen2, then the above combo makes the most sense and would be a really potent player, but it will still be quite costly. The gen2 mr2 isn't cheap to make fast. The best dollar to speed ratio I've ever seen on an mr2 belongs to mr2driver, and he certainly didn't need a standalone on his gen3 to run a 12.37.