To be honest, I don't find the E46 M seats any more supportive than the E46 sport seats.

I ended up going with recaro pole positions in my M3 and I love them. I find them more comfortable than the stock seat and night and day difference on track/spirited driving. But it is hard to ignore that they do compromise ingress/egress pretty heavily. It's even a bit embarrassing taking a 'non-car person' for a drive since they take a bit of practice getting in and out of.

 

It's possible to strip down your current sport seats and use a ratchet strap to make the kidney bolsters fit you tighter. Other members here have done it with positive results.

 

Yes, I did this with mine. I also cut some foam from the bottom of the lower section to get me to sit lower.

It massively improved the side bolstering, but I still slide around more than I want. I also simply don't find the sports seats very comfortable. I've been on the lookout for a set of E63 sports seats for what feels like an eternity, but every set I find is either wildly overpriced or too tatty for me to use.

Note to the OP: aside from the embossed "M" in the headrest, there is basically no difference between seats from an E63 with the sports package and seats from an E63 M3.

 

A Special Edition, nice!
0. Refurbishing foams would help, but I think you'll see more difference in the seat pan and not the backrest, which is what you want.
1. Foams from M3 themselves aren't much better for side support, as the intention was for them to be supplemented by backrest width adjustment (inflatable bolsters).
2/3 pretty much the same, E63 having slightly more upper body support. E63 also doesn't look to different from sedan sportsitz, but you do have the egress lever etc.
4 don't know much about these, but I think the foams are not significantly different. Also no backrest width adjustment from factory so would have to retrofit
5/6/7 Yep, if you track these might be the best option. Just depends on your budget.

Needless to say you will struggle to find those other seats in the matching Individual colour.
The backrest width button can be placed somewhere on the manual seat side I'm sure, but don't remember if it requires the memory seat control panel (which you obviously don't have).

If you already have the idea of which seats you like (E92 M3), you could explore getting those foams to put on your seat frame. But won't be easy/cheap

 

I am in Europe.
I have E63 M6 seats in my 325TI.
Very easy conversion, all I did was swapping seatbeat receivers.

 

Looks like you have an individual interior with two-tone seats and steering wheel, leather covered door handles, etc. This is quite rare and special and it looks to be in great condition. I vote for option 0!

 

Looks like steerig is not oem leather.
I did same to my steering wheel ( stitched by myself).

 

Those seats are unique and awesome. I would not get rid of them and finding new foam with some cleaning of the leather is the route I would go.

 

Thanks all for the inputs.

Yes the leather was replaced on the steering wheel already by the previous owner, but AFAIK it was looking very similar when it came out from the factory, because of the special edition trim.

I'm leaning to 0(/1) options with new foams (with that side bolstering improvement as mentioned in the thread) plus a refurbish.

 

Just saw this thread. I retrofitted used heated electric sports seats to my Touring in 2010 and used heated electric M3 seats to my coupe in 2011. I don't know the mileage on the cars they came from, but there was no wear on either set and neither looked like they'd had a lot of use. I immediately noticed the seat cushion on the M3 seats is thinner. I found the regular sports seats more comfortable on long journeys than the m3 seats. Comfort on my M3 seats comfort comes more from having them adjusted just-so, and less from the seat padding. Like how my old race car seats had no padding at all but were comfortable enough because they were moulded around me using expanding foam. Maybe the difference in padding I noticed is a Touring/saloon vs coupe thing, but I think it's more likely to be a regular-E46 vs M3 thing. I was in the coupe 6 hours yesterday (I no longer have the Touring) and was wondering about having an upholsterer add a thicker foam piece to the base. Will follow this thread to see what you decide and how it turns out

 

the seat cushion on the M3 seats is thinner.

hmm, thanks for sharing, I wasn't aware the thickness was different, in addition to the overall shape.
Might have to buy a new Sport foam to check different it is to the M3/M6 I have bought for the Contour-M3 mashup.
Although as you say, Coupe/Compact foams are different to Sedan/Touring, I doubt they differ in thickness..

So comparing 52 10 8 261 013 (E46/2 sport) with 52102695384 (M3/M6) with 52107052369 (E63 Sport), based on the few photos available, M3/M6 centre section does seem slightly thinner. E46/2 and E63 seem identical (p/n are different so assume there are slight changes).
Need to get my hands on some foams

 

Just to add to the above, the optional inflatable bolsters on M3 seats are great for holding you in. Since you mention track days.

 

That 2 tone interior looks very nice!