How about catching up with some of the Cam, Ben and myself on a weekend sometime?
We can probably give you a bit more info to help you make a decision.
You can then have a ride in any of the following:
740 Turbo with B230FT and auto (Cam)
360 with B23E, H cam and M47 manual (Cam)
240 with B230F, H cam, extractors and 2.25" exhaust, and M47 manual (Ben)
240 with B230F, H cam, extractors and 2.25" exhaust, and M47 manual (Ash)
850 T5 with B5234T, 2.5" exhaust and auto (Ash)
Each is very different, and the differences even in the 2 240s is like night and day. Depending on what your goals are you might find one of these platforms might take your fancy.
Admittedly you're not going to get an 850 for around the 5k mark, but its worth looking at for comparisons sake.
I'm not sure what Ben's 240 has cost so far, best to ask him, but 5k will certainly buy you a good starting point in a 240 or 740 and certainly something with potential.
If you want easy volvo power, then a 740T or 760T is a good starting point, a turbo 240 is a LOT more work (no factory RHD turbo 240s), but a quick N/A one is achievable to a point.