Originally Posted by m3buckeye
What about this combo:
Dinan 3.62 LSD
MRF Velaforza exhaust
My calcs show this setup to be 489hp (crank) and 396 ft/lbs of torque for those mods.
Anyone have any thoughts on these additions?
The underdrive pulley, catless or high flow cat or primary cat delete x-pipe and tune are all generally agreed to be power adders. Whether one brand adds more or less than the others seems entirely up for debate. Just use a shop or shops that you like to buy the parts the shop sells and recommends.
Obviously, of these, a catless x-pipe has less restriction than a high flow cat x-pipe or a primary cat delete x-pipe and most of the reported dynos show the catless pipes making more power. There do not seem to be many dynos showing gains from changing the rear exhaust.
The intake is a subject of debate. There are claims for power gains, but the claims have been disputed. Certainly on an older car with charcoal filter, there will be gains, but much or all of those gains might be there just from changing to a high flow filter alone.
I don't see 489 crank hp or 396 lbs torque being made from those mods. The 3.62 diff adds no engine torque. It just multiples what the engine makes. Its effect will not be reflected on an engine or chassis dyno (except perhaps as minimally greater drag on a chassis dyno).
489 crank hp would be over 400 rwhp. Search around and you will find the cars that cracked 400 rwhp SAE to be exceptionally rare. However, there are plenty of cars with the mods in your list making around 390 rwhp SAE and I don't think that works out to 489 crank hp using any realistic drivetrain loss multiplier.