I have run a modman since 2013 I think.

It works.
It will work as a bolt on. Spending time and figuring out what it wants will certainly help. I ran mine out of the box up until last year. We are index racing and I needed to slow down so I didn't care to re invent the wheel.

Last year I decided to try a few things and see what it had in it.
My observations.

1. It absolutely likes rpm. When short shifting it will work its way down track and when it gets up above 6600 it will start pulling.
2. It needs more jet than you think it does. Possibly due to less than optimal fuel distribution in the plenum.
3. You will read people talking about plenum fillers or stuffers. Do not bother. Dont decrease the flow, REDIRECT the flow.

Its a good piece and it fits under most hoods.
I am now working on a best possible combination for my car. A pair of edelbrock 750s make great mph and et. They do not react as well as my 600s did.

I have not tried staggered jetting as mentioned earlier in the thread.