When planning to modify, do I go 5.0 or X5M?

[m5james]

I've currently got an 01 X5 4.4 with a DUDMD tune, lowered on BC Racing coilovers and staggered iForged 20's, otherwise mostly stock. Even with 147k and after having been pushed to the limits from going to multiple Bimmerfest and other cars meets, she's been great...but I'm looking to upgrade.

I know this kinda sounds like a no brainer, but stock to stock isn't a fair comparison. I've tried doing a Google search, but not really finding the answers I'm looking for.

It's my understanding that the 5.0 and X5M are the same engine, just different tuning and some exchangeable parts. I watched this (https://youtu.be/4gGzq4Pyv8Q) YouTube video where they compared a modified 335i vs an M3 and it was parting hairs in performance, but the price difference, maintenance, insurance, etc between the two would be significant. Hence my curiosity about these two X5's and how the parting of hairs might be similar here as well. Ultimately I'd modify either one right away with coilvers and wheels, so the factory M suspension is irrelevant. When it comes to performance mods, if they're in fact the exact same engine, wouldn't I be able to do the exact same mods, then get to stock M power or more, for less? 5.0's are in the $30k range, yet X5M's are still in the $40k+ range...I've even seen one in NYC that's pushing upwards of 700hp, but he's asking $64k. With the same mods, wouldn't one be able to achieve those same numbers on the lower priced 5.0 platform?

I hope you guys see where I'm going with this question. M power without the M price, it seems theres no reason it can't be done, but I figured you guys would know best as to why I shouldn't.