Yeah GPS will be RS232 into dash. The only reason i might not run the 'motec' gps antenna is i want to use the gps antenna i already have on my car, which is a round hockey puck thats a bulkhead mount, so you dont see the wiring out the side of it or have to run it through a grommet on the roof ect, but the antenna is just an antenna, as the racepak dash just had a sma connector for the antennas coax, so prob get the racegrade adapter
http://racegrade.com/gps_v2.html and will prob still be 10hz, unless the 20hz isnt too much more $$
Went the M hundred series instead of the M1 series only cause i guess its much more well known, much more people know them inside and out compared to M1, and im sure the M880 can handle my simple motor.
Eventually ill have pro logging on and i2pro, no point untill the cars going. I have 2 replay xd cameras in the car already, hardwired and has autostart ect, but yeah any data overlay will have to manualy done, so realy want a HDVCS, very expensive for the picture quality, and most videos ive seen it looks like the data is updated at 0.5hz ha ha, nothing special but very convenient, i have been talked out of buying one but lets just say i have a space reserved for one on the electronics plate on the passenger footwell, and will have a spare CAN connection there, as i know ill end up getting one oneday.