Im going to replace my alternator and British Pacific specifies I need STC2784 which they said is a 100 amp alternator for $299 (new). The one that is currently on my Rover shows it to be 120 amp? Through rover connection they show the alternator for this year to be AMR2938 Marrelli Densoand that is a 120 amp for $325. I remove the EAS and have the coil suspension and plan on putting on a sound system early next year (approx. 900watts)... would it be best to go with the 100 or 120 amp?

Thanks