Exactly my thoughts, H202.

Plus the fact, why would anyone want to substitute a mechanical IP for an electrical IP?

There is no need for replacing a 603 with a 606, unless your 603 is already needing a rebuild. Mauri replaced his 603 engine with a 606 because the 603 he had before was already tired when he had first bought it.

__________________
1987 300SDL (324000)

1986 Porsche 951 (944 Turbo) (166000)

1978 Porsche 924 (99000)

1996 Nissan Pathfinder R50 (201000)