2001 HO 6sp, Bully Dog III's, Comp with Wire tapped, >100k on this combination, 450hp/980t Flat towing 35ft TT, no EGT problems, hills I have to watch, of course the backhoe is fun. The nice thing about the boxes, they are adjustable. Injectors aren't, of course with 275's that won't be a problem. Clutch handled the III's fairly well, with the box not a chance, would slip the clutch at 75mph. So more money went in, SB FE.
Money, Money, Money... ... ... That is the slippery slope, remember if you do this, you will have to do that. So plan ahead. Decide what you want now, and plan for that level, I suggest you drive someone else's truck to decide your desired power level. Remember, getting the power is easy... . getting it to the road, and keeping it cool are what really cost. If I drive like granny I can still get ~21mpg.
You need more gauges, I have three on the left and one on the column.