I actually found the bottom and the front-most side the most annoying the do. These were the sections i used the smallest and most pieces of tape. The ribbed areas you can either make an incision and split it over each side of the rib or just tape over the rib and press it down on the centre (looks neater).
For the post MAF tubes, i'd probably recommend the neoprene heat resistant mitt material i used on the tubing where the MAF sensors are mounted. Cant seem to find a source to buy this stuff in bulk (or as sheets) though
I think i'm still keen on getting silicone replacements for the post MAF accordions.
I'll upload some pics of my airboxes (they look like charcoal chickens wrapped in foil!)