Upgrading phono stage for Denon DL103?

Hi, currently using the internal phono stage of my McCormack RDL1 with a Denon DL103 on a Michell TecnoDec. I wish to upgrade to get a fuller bolder sound, which way should I go: external phonostage or newer cartridge (not both please!!!!) I think the Denon could use a better MC stage but I may be wrong. Thanks for helping.
Look at the 10 Audio review of the Bob's Devices SUT. I had actually bought one before I saw the review but I have found what he says in line with what I hear with mine. My Blue Circle didn't need a SUT and sounded good already but the SUT improved the bass and detail to a surprising degree. Just a satisfied user.
You can build the Cinemag SUT yourself for $200 less. The same for Altec 4722 depending on the current Ebay price.

Go to Audio Asylum's vinyl section and type "Cinemag" or "Altec". You will find diagrams for correct grounding scheme for each model. There's no magic to it, only to those who are not inclined to learn.

I normally as a habit DON'T chime in on these threads,but I MUST second Amandarae's suggestion regarding the Altec Peerless 4722.

I too own a DL-103 (not "R") and just so happened to have a vintage circa. 1978 Denon T-320 step-up that was mated with a damaged 103.At first I was VEY satisfied with the sound ,as I figured this was how Denon intended the it to sound.

Well! I really can't tell you why but I ended acquiring a custom made Altec 4722 step-up and all I can say is WOW! this really let the 103 "breathe" the sound be came more nuanced,detailed,more texturally DENSE,,,etc,etc. and EXPANSIVE ..... try it you'll see
I also believe the BOB Devices' SUT are very good as well they are very well designed although for a little more coin.
I would start here and then you may be satisfied with the changes rendered.Question does the McCormack have a MM input? If so you would need to have the 4722's wired for a 38 ohm load.I had mine built with a toggle that allows me to switch between 38 & 100ohm resistance.

If you have any questions feel free to private mail me
Try the inexpensive $450 Jolida JD-9A MM/MC phono preamp. It's a high gain tube unit with very flexible cartridge loading adjustments. Should provide more than enough gain for the low output Denon DL-103. It has up to 95 dB of gain via its high output connection. The Jolida is a great sounding and well made unit!