i know the guy that used too/ gets these made up i had the booklet that showed some comparisons and improvements on 3 different dyno,s with different spec engines aswell.

not sure if i still have it but the one thing i recall was a big gain in terms of the egt being alot more even on each cylinder .

You could see from the figures how 1 and 4 cylinder suffers with the standard inlet.

I,ve just found the paperwork here,s a quick example they have printed if anyone is interested. 1 engine/guide obviously with results

500 hp engine (no spec) 500 inlet and TB difference
rpm psi cyl temps 1 2 3 4 av.mean temp c 1 2 3 4
4.5k 32 648 665 687 628 657 -9 +8 +30 -29
5k 30 614 630 641 590 619 -4 +11 +22 -29
5.5k 30 634 666 676 619 649 -15 +17 +27 -30
6k 30 620 634 651 604 627 -7 +7 +24 -23


sod writing the hart results down lolpmsl , but the 4 mean ex temp figures for the hart are, 596,651,681,683 respective of rpm. The cyl mean difference is as follows

1 2 3 4
+16 -18 +2 0
+11 -13 +7 -4
+3 -8 +9 -3
+2 -8 +2 +5 You can see cyl 1 and 4 are down the majority of the time , this plenum evens things out very well (easy to see in booklet)

As you can tell i have some spare time + being quite bored haha sorry 4 that but hope it helps a little even though its a bit sketchy on the diagram i made

Mike balls its come out horrid. scan through it, u maybe able to make it out. sorry guys my fault, was only trying to help .
Basically, buy one if your after realible big power with even inlet intake system