I am not familiar with you plane I will assume it is a brushed motor if it is smaller than a speed 400 and you do go to lipo I recomend a 2 cell the three cell lipos burn up the smaller motors pretty fast but with you price constraints (i feel you ) just stick wth a nicad but increase yoe mah Ie if you have a 800mah go to a 1500mah battery but dont forget to check your center og gravity it is very difficult to fly an out of balance plane. also when you make the plane heavier (larger batery pack etc you will have to fly it faster. Hope this helps.