hi guys im debating which one should i do if the j mod or a tune to make my transmission shift better i just cant stand the way the car shifts from first to second waay to slow and sluggish now i have a bbk intake dual exhaust and planning on getting the intake spacer and my last mod was going to b a tuner but idk if its worth it for just those mods because all i really want are the better transmission shifts and to correct my speedometer with my rims any help would be apreciated thank you

 

Do both of them. Tuner increases pressure while the j mod increases flow. I've heard great things from people who have done both.

 

If you do both, I'd get a transmission cooler as well. Also, he doesn't sell jmod plates anymore, you have to take yours out, ship it to him, and re-intall it like a week later. If your mustang can be down for a week, do it.

 

Or you can just buy another valve body, ship that to him and then when it gets back ship the other to him and sell it when you get it back.

I wouldnt try to make a profit off of it, take a small loss for the convenience of not having your stang down.