i need recommendation and a little help

hi! is ipod nano 3rd gen or ipod classic 4 gen is easier to mod

i was looking for iPods, and they are crazily overpriced on my local websites, but i found some fairer price iPod nano 3rd gen and iPod classic 4th gen. nano's battery needs to be replaced and ipod classic's battery + hdd needs to be replaced (which is fine cuz i want to mod them already, i also found a 160 gb hdd not sure if it suitable for 4th gen though, im not knowledgeable in ipod modding). i have some knowledge on modding techs, but iPod is whole another level for me. which one is easier to mod as a beginner?