I think it's worth mentioning that the RX8 is a completely different experince to all the other options that have been mentioned. Someone moving from a skyline to an RX8 should be aware of a few things...
Firstly in relation to the engine, power is delivered very smoothly and without fuss. There is a slight peak from about 5k onward to 9.5k. There is not a great deal of torqe forcing you into the seat like a turb coming on boost. If this is what you are after, do not buy an RX8 unless you're happy with the power/torque or planning for FI or other significant conversion. Having said this, the stated power/torque figures don't quite capture the whole experience of accelerating in an RX8 however more power/torque would be welcome if the opportunity arose.
Secondly the handling is brilliant. By that I mean that moving from a spirited driving mindset to a comfortable traffic driving mindset is pretty much transparent. Seriously an exciting/thrilling drive. I'm aware of some criticism of other vehicles in that they are not able to achieve a good balance. Again if you want something more track oriented perhaps you need to look at improving the suspension with aftermarket parts, or going elsewhere.
Thirdly the interior and build quality is a cut above the other options. The materials and design of the interior compliments itself. I was disappointed in the quality of other interiors, although i have to say the Liberty GT with the STI pack and McIntosh sound system was pretty impressive. The BOSE sound system in the RX8 is good enough unless you want to impress the crowd outside TGIs on Chapel. Then you need to look at aftermarket. When compared to the 3 & 6 MPS the interiors feel significantly more vanilla. The seating position is far more upright. I guess its all about trying to upgrade a 20-30k car to a 40-50k package? e.g. the gear boot on the 3 & 6 feels really thin, knobs on the climate controls are nasty...
i could go on but i cbf...
All in all, if you're still uncertain as to what you should buy keep test driving until you decide. If someone really wants to sell you something they will hand you the keys time and time again.
Also accept the fact that the car you pay for will be the car you take home, by that i mean its not going to magically get more comfortable or more powerful on the way home. Modifications cost $. Plan with contingency in mind...
P.S. That was definately longer that i thought... Hope the read was worth it...