Mike,
Plenty of guys have done the V6 conversion and kept stock brakes on the front, and the tiger did use the alpine brakes (not saying great in the case of the tiger, but they did it) the V6 conversion doesnt add much in terms of weight. You could use the volvo 4 piston calipers on the stock rotors, or the m16 willwoods.
Dale A also offers a kit to bolt vented rotors onto the stock setup and calipers.. and also offer 2 upgarde kits of willwood vented rotoea and 4 pistons... 10.5 and 12 inch.
As for rear, most guys use a narrowed ford 8 inch, good selection on ratios.. the alpine unit is ok if you get some hardened woodruf keys (jim ellis has those)
If you are gogin V6 i strongly suggest you contact Jose Rodriguez about his V6 conversion kit... also read the SAOCA site, there is a whole forum dedicated to the v6 conversion.