I hadn't realised that slang forms like すげぇ and こえぇ were more a Kanto thing. My husband, born and bred in Kanagawa and now living in Tokyo, uses both all the time. He uses びっくりした in different situations than he would こえぇ- びっくりした for when something actually startles him, whereas こえぇ is for something genuinely scary, like the glass floors they have in towers sometimes- he doesn't like heights
On thinking about it women seem more likely to say きもっ, whereas guys will use the えぇ ending more. I can't ask my husband to confirm right now because he's still at work at 11pm- luckily not a typical situation!
Interesting that 分かんない is a Kanto thing too- it's true that you don't often hear people say 分からん here.