Would normally recommend Motad but someone on here had quality issues & trouble getting them to respond to emails/phone calls & they are a lot more than the ones you have mentioned,but I think I would go for the Delkevic ones as they have the the connecting pipes between 1-2,3-4 as originals it may pay you to get a new exhaust can at the same time if it works out cheaper together it would look better than putting the original one back on if that's what you've got. You will need most lightly to have carbs balanced after fitting the new downpipes.
Start spraying those exhaust studs now with Plusgas not WD-40 to hopefully avoid snapping studs on removal.