Nissan Sentra Series 3 (USED)

guys, help me naman on how to defend the car that i want, kasi my parents would buy me a car. pero kung ano-ano suggestions nila na ayaw ko naman in short, sila namimili para sakin. ano kaya pwede ko sabihin na ma convince na ok naman ang nissan sentra series 3 . sinasabi nila na mabigat daw masyado ang sentra (sa parts, fuel consumption at kung ano-ano pa) ang alam lang nila is TOYOTA lang ang tipid. hayyyyy