You will definately need convex mirrors for your iva, they are very strict on the fields of vision
Also mount them as high up on the scuttle as you can so the rear arch causes as little obstuction to the view as possible, they almost got me on this one but a quick yank on the mirror and all was fine
I think the only disadvantage to convex is things may appear to be further away or closer (cant remember which) than they actually are but the field of view is much better.