Hi gill, i have an alhambra which as you will know is exactely the same as the galaxy and the upgrade i have is just a box that slots on to the diagnostics socket, you clip it on press a button and the unit downlods the new software to the engine management computer. my alhambra started of at 130 bhp, with the box fitted it is 172 bhp and 380 pound of torque, there is no adjusting to do the box does it all. there are many upgrades availlable and some should be left well alone, make sure you research your suplier before buying and get some feedback from people who have used the upgrade. i can definately recommend the dual system that i have which costs 475 pounds from a company called awsome gti in manchester. if you have the 115 bhp galaxy i think the dual system puts it up to 150 bhp but check out theire web site it has all the maps to look at.
Caravan Battery we think is dead even though we have solar