The NAG1 install required modifying the transmission cross member to create a proper mount. I used an alterktion front suspension so the torsion bar mounts were not going to be an issue . If you are keeping the stock suspension you would want to look at how the NAG transmission mount would affect that need. The floor raised up maybe 3/4" at the hump.
Having been through this I STRONGLY suggest going with Sound German Automotive. Russell Drake is the gentleman who owns that outfit and he has the programming down pat. It might take a few back and forth data saves but he will get it dialed for you and HE IS VERY RESPONSIVE! I would not get into this with anyone who admits they are still dialing it in, we are truly talking rocket science stuff....line pressures vs throttle position vs rpm vs torque converter lockup.......Russell Knows this stuff inside and out. He has returned program updates in as little as a few hours.
It was worth all the hassle and expense (to me anyway) This set up performs better than I had even imagined and I have averaged 20mpg on long hauls averaging at least 10 mph over.
I don't know if Russell is selling this unit direct but I would start with him. I bought my unit through an outfit called PCS and they sent me to Russell when they couldn't figure it out.