Ok there are 7 speakers in the SV6:
- Centre Dash Speaker... This speaker has a habit of distorting. I would look at replacing, or even removing it as I think it is pointless
- 2 Front Speakers... Replace these with splits, they'd be either 5.25 or 6" but im not sure which
- 2 Rear Speakers... I would replace these. Stock size is 5" or 5.25" but you'd be better off replacing them with 6" co-axials. There is room, just remove the plastic mounting bracket and replace with a 6mm MDF ring
- 2 In dash tweeters... Replace these with the tweeters that come with the front splits.