TM3 underpowered. Best upgrade?

I work at an industrial fab shop and we recently inquired a TM3 as well as a tl3 and waterjet table as we have been outsourcing machine work. At the time, I really didn't know exactly what we were going to be doing, and now that I do, I am finding the tm3 is simply underpowered as I am constantly finding the tool imbalance and spindle overload alarms going off. We run everything from 1018 to ar400 but no aluminum. Some UHMW, but for the most part, it's harder metals. A lot of 3/8 and 1/2" tapping, as well as 3/4. I am finding a 1/2" Guhring coated tap can't be ran over 50 rpms otherwise it will overload the spindle. Yes, max tourqe is around 1500 rpms, but that's over twice the recommended sfm. All 5/8 and 3/4 tapped holes have been threadmilled and anything deeper than 1 1/4 dp has to be brought over to our gear driven radial drill. I recently ran some stainless parts with a redline hpx 5 flute to the optimum axial and radial loads. And at the lowest sfm and feed, I was at 130% spindle load. At the middle of the recommended range, I was pushing 190%.

Yes, I have making this mill work, but at the same time I feel like I am running it to its max, which is less than where my tooling should be which in turn kills the tooling. So before it gets to the point where the machine says it's had enough, we are considering options for upgrading. We also have to send out shaft collars to be internally broached so the upgrade should have this option. The machining is a small portion of the company, hence the reason for the less expensive machine. I have been looking at the VF-4 as a possibility. Another factor to consider is all my tooling are cat40 which is a good chunk of change.

What are your thoughts? The tm3 is the only CNC I have ran so hopefully you guys can help me make the right decision!

There's only so much you can do power wise with a TM3. It sounds like your needing a slower higher torque machine, and a VF4 shouldn't be on that list IMHO unless it's a 50 taper...
There are SO Many different choices to choose from other than HAAS at about the same price point! Doosan, Samsung, Kitamura, Mazak, slightly used Mori or the like.
Although a VF4 will do much better than a TM, there's so much better out there. We have a Mori and a HAAS right next to each other, so I know the differences.
FYI if at all possible I threadmill anything over 1/2" even in a "real" VMC.
Take your time and look around before you make any decisions on a machine.

nah, VF 40taper with a gearbox should be more than adequate for a non production shop. Ease of use of the control is a bigger factor then balls out performance (once you get past the toymill models), IMHO, of course.

but if you don't want to skimp you could go with their 50taper models. They got lots of nuts.

If you want to keep your tooling there are better machines for not a huge increase in money, like rstewart said.
top on my list is Okuma genos in the 40 x 20 size.