M3 Convertible topside bar and x brace

[siamkazi]

Hey All, I'll be getting my subframe reinforced soon, was searching for options that fit the convertibles and came across this gentleman. Seems like his will fit the bill in terms of what needs to be addressed from the top side. Not sure if anyone else is interested, i'm not affiliated in any way for transparency purposes, just passing on what i've seen and heard.

https://www.s-m-eng.com/product-page/sme-combo-kit

[Nate047]

Unfortunately there is no consensus on this subject. Everyone who makes products for this area have reasons why theirs is the best and the others are wrong.

I am not an expert by any means, but I’ve read and listened to a lot of people who are, and my takeaway is that if it’s a track car and you don’t care about trunk space or keeping OEM looks, a 6-point topside brace should be adequate. You don’t necessarily need to do a bolt in X brace on top of a Vince bar type weld in brace. It can’t hurt I suppose but it’s just a question of how far you want to go. Some sort of reinforcement on the chassis legs is probably smart.

The SME setup looks good, it doesn’t address the front 2 mounts at all though which is odd. But again, if you ask a dozen experts about this, none of them will agree. So you have to just make a decision that works for you and go with it.

[siamkazi]

Unfortunately there is no consensus on this subject. Everyone who makes products for this area have reasons why theirs is the best and the others are wrong.

I am not an expert by any means, but I’ve read and listened to a lot of people who are, and my takeaway is that if it’s a track car and you don’t care about trunk space or keeping OEM looks, a 6-point topside brace should be adequate. You don’t necessarily need to do a bolt in X brace on top of a Vince bar type weld in brace. It can’t hurt I suppose but it’s just a question of how far you want to go. Some sort of reinforcement on the chassis legs is probably smart.

The SME setup looks good, it doesn’t address the front 2 mounts at all though which is odd. But again, if you ask a dozen experts about this, none of them will agree. So you have to just make a decision that works for you and go with it.

Hey Nate047 - Sincerely appreciate the insight, I'd concur with you. As much 'research' as I did, it came back to what you stated: 'no consensus on the subject' so will probably do some soul searching as to what I'm trying to potentially achieve.

The setups on the coupes are really cool btw, for whatever reason each owner went with.

[Gt4]

I installed CMP underside & topside reinforcement in a friend convertible in October. I really like their products. It can almost look like factory once installed.

You could also installed a brace with CMP cause they have threaded insert on top of rear subframe mounts. CMP offer brace options also

This is my LSB Coupe but it will look the same in convertible.

[stephen]

I installed CMP underside & topside reinforcement in a friend convertible in October. I really like their products. It can almost look like factory once installed.

You could also installed a brace with CMP cause they have threaded insert on top of rear subframe mounts. CMP offer brace options also

This is my LSB Coupe but it will look the same in convertible.

I have a full CMP topside on my sedan with both bolt in braces. Can’t argue with the fit and function especially for the money. Their kits are surprisingly affordable.

[siamkazi]

Gt4 - This is great info given you actually worked on a convertible ,thanks so much for the info and picture!

stephen - Appreciate the insight, you weren't kidding about affordability


I reached out to Cayne from CMP, he's borrowing a convertible in his part of the woods to check fitment. From initial pictures etc, he thinks it's possible to also utilize the brace as well (in addition to the topside beam) without any modifications. Will report back once it's confirmed.

[VisorM3]

any updates siamkazi ?

[siamkazi]

any updates siamkazi ?

Hey, I actually have a order from Yurkan (Marin is his name) for a V2 version, should be ready in 30 days or so per his schedule, he just released this in late January and seems like he has some good thought put into it.

https://yurkancages.com/en/bmw-e46/

[VisorM3]

Cool thanks!
Shopping for a vert now and people always say they are much less rigid than the coupes (obviously!, and heavier) so was wondering what was out there to stiffen them up (and help the subframe) so I found your thread