Shorty headers are generally a waste of time and the gains from them are mostly because they are new and free of carbon build up. Long tubes offer a better bang for the buck and are proven performers. I understand that the cost of long tubes or a complete long tube, cats and x-pipe are expensive but if you do it right the first time you're not re-doing it later, and spending even more money. The exception to the rule would be LT1 F-bodies(Camaro/Firebird) which are brutal for space or if you did a swap like an LS motor in say a '57 Bel Air and that's all you can squeeze into place. Not to sound preachy, but go with LG's and a tune from Manny and you won't be disappointed. There was a good point I believe from Colin too, which was to make sure that the air in, matches the air out.