I think you have to remember where the M62 sits in the range of BMW V8's.

It was not originally designed to be a high performance engine.. more like a lumbering lump to power exec barges.

Originally launched in 1996 in 3.5 guise for the larger saloon/limo market. None were in the "M" variants which BMW tended and till reciently kept to S6 engines.

This was the staple diet of the M series V8 until it's upgrade with Vanos N variant.

At this juncture it was developed for use in the Z8 giving a 5.0 400hp unit with much similar and simple techniques as the Audi engine... maybe a good comparison.. roughly the same era.

Interestingly a very high performance veriant of this engine lives on today in Ascari A10. @ 625bhp... probably a continuation of the S62 development.

So in the grand scheme of things.. BMW did have a high performance version.. it just was not sold in huge numbers and ultimately was fitted into generally un-sporty barges and 4x4's. With the tuning complication of Vanos most of the post M62 engines were not touched by tuners or racers as they were esentially electronically complicated and expensive to enhance....

Hence the situation we have today... M/N series performance parts are few and far between the the modifications above are not all possible with the later VANOS engines... seeminly major cylinder head work/modification is requried to remove/sort it out.

Unfortunately this leaves the Morgan market too small to generate the parts requried and the BMW market is already shrinking with the M5 V8's and the X5's bieng slowly replaced with newer series engines and Diesel S6 turbo units.

So Aero tuning is a deep pockets game with simple modifications such as cams costing well into the thousands to obtain.. TBH.. Tiger racing in the USA had the cheap solution.. going Chevy LS1 for their race cars.. 700bhp available at a pretty low cost per hp.